Methods of administering/dosing anti-RSV antibodies for prophylaxis and treatment

ABSTRACT

The present invention encompasses novel antibodies and fragments thereof which immunospecifically bind to one or more RSV antigens and compositions comprising said antibodies and antibody fragments. The present invention encompasses methods preventing respiratory syncytial virus (RSV) infection in a human, comprising administering to said human a prophylactically effective amount of one or more antibodies or fragments thereof that immunospecifically bind to one or more RSV antigens, wherein a certain serum titer of said antibodies or antibody fragments is achieved in said human subject. The present invention also encompasses methods for treating or ameliorating symptoms associated with a RSV infection in a human, comprising administering to said human a therapeutically effective amount of one or more antibodies or fragments thereof that immunospecifically bind to one or more RSV antigens, wherein a certain serum titer of said antibodies or antibody fragments is achieved in said human subject. The present invention further encompasses compositions comprising antibodies or fragments thereof that immunospecifically bind to a RSV antigen, and methods using said compositions for detection or diagnosis a RSV infection.

This application is a divisional of U.S. application Ser. No.09/996,265, filed Nov. 28, 2001, now U.S. Pat. No. 6,855,493, issued onFeb. 15, 2005, which is a continuation-in-part of U.S. application Ser.No. 09/724,396, filed Nov. 28, 2000, now abandoned, the entire contentsof each of which is incorporated herein by reference.

1. INTRODUCTION

The present invention relates to compositions comprising antibodies orfragments thereof that immunospecifically bind to a RSV antigen andmethods for preventing, treating or ameliorating symptoms associatedwith respiratory syncytial virus (RSV) infection utilizing saidcompositions. In particular, the present invention relates to methodsfor preventing, treating or ameliorating symptoms associated with RSVinfection, said methods comprising administering to a human subject aneffective amount of one or more antibodies or fragments thereof thatimmunospecifically bind to a RSV antigen, wherein a certain serum titerof said antibodies or antibody fragments is achieved in said humansubject. The present invention also relates to detectable or diagnosticcompositions comprising antibodies or fragments thereof thatimmunospecifically bind to a RSV antigen and methods for detecting ordiagnosing RSV infection utilizing said compositions.

2. BACKGROUND OF THE INVENTION

Respiratory syncytial virus (RSV) is the leading cause of serious lowerrespiratory tract disease in infants and children (Feigen et al., eds.,1987, In: Textbook of Pediatric Infectious Diseases, W B Saunders,Philadelphia at pages 1653-1675; New Vaccine Development, EstablishingPriorities, Vol. 1, 1985, National Academy Press, Washington D.C. atpages 397-409; and Ruuskanen et al., 1993, Curr. Probl. Pediatr.23:50-79). The yearly epidemic nature of RSV infection is evidentworldwide, but the incidence and severity of RSV disease in a givenseason vary by region (Hall, C. B., 1993, Contemp. Pediatr. 10:92-110).In temperate regions of the northern hemisphere, it usually begins inlate fall and ends in late spring. Primary RSV infection occurs mostoften in children from 6 weeks to 2 years of age and uncommonly in thefirst 4 weeks of life during nosocomial epidemics (Hall et al., 1979,New Engl. J. Med. 300:393-396). Children at increased risk from RSVinfection include preterm infants (Hall et al., 1979, New Engl. J. Med.300:393-396) and children with bronchopulmonary dysplasia (Groothuis etal., 1988, Pediatrics 82:199-203), congenital heart disease (MacDonaldet al., New Engl. J. Med. 307:397-400), congenital or acquiredimmunodeficiency (Ogra et al., 1988, Pediatr. Infect. Dis. J. 7:246-249;and Pohl et al., 1992, J. Infect. Dis. 165:166-169), and cystic fibrosis(Abman et al., 1988, J. Pediatr. 113:826-830). The fatality rate ininfants with heart or lung disease who are hospitalized with RSVinfection is 3%-4% (Navas et al., 1992, J. Pediatr. 121:348-354).

RSV infects adults as well as infants and children. In healthy adults,RSV causes predominantly upper respiratory tract disease. It hasrecently become evident that some adults, especially the elderly, havesymptomatic RSV infections more frequently than had been previouslyreported (Evans, A. S., eds., 1989, Viral Infections of Humans.Epidemiology and Control, 3^(rd) ed., Plenum Medical Book, New York atpages 525-544). Several epidemics also have been reported among nursinghome patients and institutionalized young adults (Falsey, A. R., 1991,Infect. Control Hosp. Epidemiol. 12:602-608; and Garvie et al., 1980,Br. Med. J. 281:1253-1254). Finally, RSV may cause serious disease inimmunosuppressed persons, particularly bone marrow transplant patients(Hertz et al., 1989, Medicine 68:269-281).

Treatment options for established RSV disease are limited. Severe RSVdisease of the lower respiratory tract often requires considerablesupportive care, including administration of humidified oxygen andrespiratory assistance (Fields et al., eds, 1990, Fields Virology,2^(nd) ed., Vol. 1, Raven Press, New York at pages 1045-1072). The onlydrug approved for treatment of infection is the antiviral agentribavirin (American Academy of Pediatrics Committee on InfectiousDiseases, 1993, Pediatrics 92:501-504). It has been shown to beeffective in the treatment of RSV pneumonia and bronchiolitis, modifyingthe course of severe RSV disease in immunocompetent children (Smith etal., 1991, New Engl. J. Med. 325:24-29). However, ribavirin has hadlimited use because it requires prolonged aerosol administration andbecause of concerns about its potential risk to pregnant women who maybe exposed to the drug during its administration in hospital settings.

While a vaccine might prevent RSV infection, no vaccine is yet licensedfor this indication. A major obstacle to vaccine development is safety.A formalin-inactivated vaccine, though immunogenic, unexpectedly causeda higher and more severe incidence of lower respiratory tract diseasedue to RSV in immunized infants than in infants immunized with asimilarly prepared trivalent parainfluenza vaccine (Kim et al., 1969,Am. J. Epidemiol. 89:422-434; and Kapikian et al., 1969, Am. J.Epidemiol. 89:405-421). Several candidate RSV vaccines have beenabandoned and others are under development (Murphy et al., 1994, VirusRes. 32:13-36), but even if safety issues are resolved, vaccine efficacymust also be improved. A number of problems remain to be solved.Immunization would be required in the immediate neonatal period sincethe peak incidence of lower respiratory tract disease occurs at 2-5months of age. The immaturity of the neonatal immune response togetherwith high titers of maternally acquired RSV antibody may be expected toreduce vaccine immunogenicity in the neonatal period (Murphy et al.,1988, J. Virol. 62:3907-3910; and Murphy et al., 1991, Vaccine9:185-189). Finally, primary RSV infection and disease do not protectwell against subsequent RSV disease (Henderson et al., 1979, New Engl.J. Med. 300:530-534).

Currently, the only approved approach to prophylaxis of RSV disease ispassive immunization. Initial evidence suggesting a protective role forIgG was obtained from observations involving maternal antibody inferrets (Prince, G. A., Ph.D. diss., University of California, LosAngeles, 1975) and humans (Lambrecht et al, 1976, J. Infect. Dis.134:211-217; and Glezen et al., 1981, J. Pediatr. 98:708-715). Hemminget al. (Morell et al., eds., 1986, Clinical Use of IntravenousImmunoglobulins, Academic Press, London at pages 285-294) recognized thepossible utility of RSV antibody in treatment or prevention of RSVinfection during studies involving the pharmacokinetics of anintravenous immune globulin (IVIG) in newborns suspected of havingneonatal sepsis. They noted that 1 infant, whose respiratory secretionsyielded RSV, recovered rapidly after IVIG infusion. Subsequent analysisof the IVIG lot revealed an unusually high titer of RSV neutralizingantibody. This same group of investigators then examined the ability ofhyperimmune serum or immune globulin, enriched for RSV neutralizingantibody, to protect cotton rats and primates against RSV infection(Prince et al., 1985, Virus Res. 3:193-206; Prince et al., 1990, J.Virol. 64:3091-3092; Hemming et al., 1985, J. Infect. Dis.152:1083-1087; Prince et al., 1983, Infect. Immun. 42:81-87; and Princeet al., 1985, J. Virol. 55:517-520). Results of these studies suggestedthat RSV neutralizing antibody given prophylactically inhibitedrespiratory tract replication of RSV in cotton rats. When giventherapeutically, RSV antibody reduced pulmonary viral replication bothin cotton rats and in a nonhuman primate model. Furthermore, passiveinfusion of immune serum or immune globulin did not produce enhancedpulmonary pathology in cotton rats subsequently challenged with RSV.

Recent clinical studies have demonstrated the ability of this passivelyadministered RSV hyperimmune globulin (RSV IVIG) to protect at-riskchildren from severe lower respiratory infection by RSV (Groothius etal., 1993, New Engl. J. Med. 329:1524-1530; and The PREVENT Study Group,1997, Pediatrics 99:93-99). While this is a major advance in preventingRSV infection, this treatment poses certain limitations in itswidespread use. First, RSV IVIG must be infused intravenously overseveral hours to achieve an effective dose. Second, the concentrationsof active material in hyperimmune globulins are insufficient to treatadults at risk or most children with comprised cardiopulmonary function.Third, intravenous infusion necessitates monthly hospital visits duringthe RSV season. Finally, it may prove difficult to select sufficientdonors to produce a hyperimmune globulin for RSV to meet the demand forthis product. Currently, only approximately 8% of normal donors have RSVneutralizing antibody titers high enough to qualify for the productionof hyperimmune globulin.

One way to improve the specific activity of the immunoglobulin would beto develop one or more highly potent RSV neutralizing monoclonalantibodies (MAbs). Such MAbs should be human or humanized in order toretain favorable pharmacokinetics and to avoid generating a humananti-mouse antibody response, as repeat dosing would be requiredthroughout the RSV season. Two glycoproteins, F and G, on the surface ofRSV have been shown to be targets of neutralizing antibodies (Fields etal., 1990, supra; and Murphy et al., 1994, supra). These two proteinsare also primarily responsible for viral recognition and entry intotarget cells; G protein binds to a specific cellular receptor and the Fprotein promotes fusion of the virus with the cell. The F protein isalso expressed on the surface of infected cells and is responsible forsubsequent fusion with other cells leading to syncytia formation. Thus,antibodies to the F protein may directly neutralize virus or block entryof the virus into the cell or prevent syncytia formation. Althoughantigenic and structural differences between A and B subtypes have beendescribed for both the G and F proteins, the more significant antigenicdifferences reside on the G glycoprotein, where amino acid sequences areonly 53% homologous and antigenic relatedness is 5% (Walsh et al., 1987,J. Infect. Dis. 155:1198-1204; and Johnson et al., 1987, Proc. Natl.Acad. Sci. USA 84:5625-5629). Conversely, antibodies raised to the Fprotein show a high degree of cross-reactivity among subtype A and Bviruses. Beeler and Coelingh (1989, J. Virol. 7:2941-2950) conducted anextensive analysis of 18 different murine MAbs directed to the RSV Fprotein. Comparison of the biologic and biochemical properties of theseMAbs resulted in the identification of three distinct antigenic sites(designated A, B, and C). Neutralization studies were performed againsta panel of RSV strains isolated from 1956 to 1985 that demonstrated thatepitopes within antigenic sites A and C are highly conserved, while theepitopes of antigenic site B are variable.

A humanized antibody directed to an epitope in the A antigenic site ofthe F protein of RSV, SYNAGIS® is approved for intramuscularadministration to pediatric patients for prevention of serious lowerrespiratory tract disease caused by RSV at recommended monthly doses of15 mg/kg of body weight throughout the RSV season (November throughApril in the northern hemisphere). SYNAGIS® is a composite of human(95%) and murine (5%) antibody sequences. See, Johnson et al., 1997, J.Infect. Diseases 176:1215-1224 and U.S. Pat. No. 5,824,307, the entirecontents of which are incorporated herein by reference. The human heavychain sequence was derived from the constant domains of human IgG₁ andthe variable framework regions of the VH genes or Cor (Press et al.,1970, Biochem. J. 117:641-660) and Cess (Takashi et al., 1984, Proc.Natl. Acad. Sci. USA 81:194-198). The human light chain sequence wasderived from the constant domain of Cκ and the variable frameworkregions of the VL gene K104 with Jκ-4 (Bentley et al., 1980, Nature288:5194-5198). The murine sequences derived from a murine monoclonalantibody, Mab 1129 (Beeler et al., 1989, J. Virology 63:2941-2950), in aprocess which involved the grafting of the murine complementaritydetermining regions into the human antibody frameworks.

Although SYNAGIS® has been successfully used for the prevention of RSVinfection in pediatric patients, multiple intramuscular doses of 15mg/kg of SYNAGIS® is required to achieve a prophylactic effect. Inpediatric patient's less than 24 months of age, the mean half-life ofSYNAGIS® has been shown to be 20 days and monthly intramuscular doses of15 mg/kg have been shown to result in a mean±standard derivation 30 dayserum titer of 37±21 μg/ml after the first injection, 57±41 μg/ml afterthe second injection, 68±51 μg/ml after the third injection, and 72±50μg/ml after the fourth injection (The IMpact RSV Study Group, 1998,Pediatrics 102:531-537). Serum concentrations of greater than 30 μg/mlhave been shown to be necessary to reduce pulmonary RSV replication by100 fold in the cotton rat model of RSV infection. However, theadministration of multiple intramuscular doses of 15 mg/kg of antibodyis inconvenient for the patient. Thus, a need exists for antibodies thatimmunospecifically bind to a RSV antigen, which are highly potent, havean improved pharmacokinetic profile, and thus have an overall improvedtherapeutic profile. Further, a need exists for antibodies thatimmunospecifically bind to a RSV antigen which require less frequentadministration.

Citation or discussion of a reference herein shall not be construed asan admission that such is prior art to the present invention.

3. SUMMARY OF THE INVENTION

The present invention is based, in part, on the development of methodsfor achieving or inducing a prophylactically or therapeuticallyeffective serum titer of an antibody or fragment thereof thatimmunospecifically binds to a respiratory syncytial virus (RSV) antigenin a mammal by passive immunization with such an antibody or fragmentthereof, which methods require lower dosages and/or less frequentadministration than previously known methods. The present invention isalso based, in part, on the identification of antibodies with higheraffinities for a RSV antigen which result in increased efficacy forprophylactic or therapeutic uses such that lower serum titers areprophylactically or therapeutically effective, thereby permittingadministration of lower dosages and/or reduced frequency ofadministration.

The present invention provides methods of preventing, neutralizing,treating and ameliorating one or more symptoms associated with RSVinfection in a subject comprising administering to said subject one ormore antibodies or fragments thereof which immunospecifically bind toone or more RSV antigens with high affinity and/or high avidity. Becausea lower serum titer of such antibodies or antibody fragments istherapeutically or prophylactically effective than the effective serumtiter of known antibodies, lower doses of said antibodies or antibodyfragments can be used to achieve a serum titer effective for theprevention, neutralization, treatment and the amelioration of symptomsassociated with a RSV infection. The use of lower doses of antibodies orfragments thereof which immunospecifically bind to one or more RSVantigens reduces the likelihood of adverse effects. Further, the highaffinity and/or high avidity of the antibodies of the invention orfragments thereof enable less frequent administration of said antibodiesor antibody fragments than previously thought to be necessary for theprevention, neutralization, treatment or the amelioration of symptomsassociated with a RSV infection.

The present invention also provides antibodies which immunospecificallybind to one or more RSV antigens and have increased in vivo half-livesrelative to known antibodies such as, e.g., SYNAGIS®. In particular, thepresent invention encompasses antibodies which immunospecifically bindto one or more RSV antigens and have increased in vivo half-livesrelative to known antibodies (e.g., SYNAGIS®), said increased half-livesresulting from one or more modifications (e.g., substitutions,deletions, or insertions) in amino acid residues identified to beinvolved in the interaction of the Fc domain of said antibodies and theFcRn receptor. The present invention also encompasses pegylatedantibodies and fragments thereof which immunospecifically bind to one ormore RSV antigens and have increased in vivo half-lives relative toknown antibodies such as, e.g., SYNAGIS®. The increased in vivohalf-lives of antibodies or fragments thereof which immunospecificallybind to one or more RSV antigens reduce the dosage and/or frequency ofadministration of said antibodies or fragments thereof to a subject.

The invention encompasses sustained release formulations for theadministration of one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens to a subject. Thesustained release formulations reduce the dosage and/or frequency ofadministration of said antibodies or antibody fragments to a subject.Further, the sustained release formulations may be administered tomaintain a therapeutically or prophylactically effective serum titerwhich does not exceed a certain maximum serum titer for a certain periodof time.

The present invention encompasses methods of delivering one or moreantibodies or fragments thereof which immunospecifically bind to one ormore RSV antigens directly to the site of RSV infection. In particular,the invention encompasses pulmonary delivery of one or more antibodiesor fragments thereof which immunospecifically bind to one or more RSVantigens. The improved methods of delivering of one or more antibodiesor fragments thereof which immunospecifically bind to one or more RSVantigens reduce the dosage and/or frequency of administration of saidantibodies or antibody fragments to a subject.

The present invention provides antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens and have anassociation rate constant or k_(on) rate

$\left( {{{{antibody}\mspace{14mu}({Ab})} + {{antigen}\mspace{14mu}({Ag})}}\overset{k_{on}}{\rightarrow}{{Ab} - {Ag}}} \right)$of at least 10⁵ M⁻¹s⁻¹, at least 5×10⁵ M⁻¹s⁻¹, at least 10⁶M⁻¹s⁻¹, atleast 5×10⁶M⁻¹s⁻¹, at least 10⁷M⁻¹s⁻¹, at least 5×10⁷M⁻¹s⁻¹, or at least10⁸ M⁻¹s⁻¹. In particular, the present invention provides compositionsfor use in the prevention, treatment or amelioration of one or moresymptoms associated with a RSV infection, said compositions comprisingone or more antibodies or fragments thereof which immunospecificallybind to one or more RSV antigens and have an a k_(on) rate of at least10⁵ M⁻¹s⁻¹, at least 5×10⁵M⁻¹s⁻¹, at least 10⁶M⁻¹s⁻¹, at least5×10⁶M⁻¹s⁻¹, at least 10⁷M⁻¹s⁻¹, at least 5×10⁷M⁻¹s⁻¹, or at least10⁸M⁻¹s⁻¹.

The present invention provides antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens and have a k_(off)rate (antibody (Ab)+antigen

$\left( {{{{antibody}\mspace{14mu}({Ab})} + {{antigen}\mspace{14mu}({Ag})}}\overset{K_{off}}{\leftarrow}{{Ab} - {Ag}}} \right)$of less than 10⁻¹ s⁻¹, less than 5×10⁻¹ s⁻¹, less than 10⁻² s⁻¹, lessthan 5×10⁻² s⁻¹, less than 10⁻³ s⁻¹, less than 5×10⁻³ s⁻¹, less than10⁻⁴ s⁻¹, less than 5×10⁻⁴ s⁻¹, less than 10⁻⁵ s⁻¹, less than 5×10⁻⁵s⁻¹, less than 10⁻⁶ s⁻¹, less than 5×10⁶ s⁻¹, less than 10⁻⁷ s⁻¹, lessthan 5×10⁻⁷ s⁻¹, less than 10⁻⁸ s⁻¹, less than 5×10⁻⁸ s⁻¹, less than10⁻⁹ s⁻¹, less than 5×10⁻¹⁰ s⁻¹, or less than 10⁻¹⁰ s⁻¹. In particular,the present invention provides compositions for use in the prevention,treatment or amelioration of one or more symptoms associated with a RSVinfection, said compositions comprising one or more antibodies orfragments thereof which immunospecifically bind to one or more RSVantigens and have a k_(off) rate of less than 10⁻¹ s⁻¹, less than 5×10⁻¹s⁻¹, less than 10⁻² s⁻¹, less than 5×10⁻² s⁻¹, less than 10⁻³ s⁻¹, lessthan 5×10⁻³ s⁻¹, less than 10⁻⁴ s⁻¹, less than 5×10⁻⁴ s⁻¹, less than10⁻⁵ s⁻¹, less than 5×10⁻⁵ s⁻¹, less than 10⁻⁶s⁻¹, less than 5×10⁻⁶ s⁻¹,less than 10⁻⁷ s⁻¹, less than 5×10⁻⁷ s⁻¹, less than 10⁻⁸ s⁻¹, less than5×10⁻⁸ s⁻¹, less than 10⁻⁹ s⁻¹, less than 5×10⁻⁹ s⁻¹, or less than 10⁻¹⁰s⁻¹.

The present invention also provides antibodies or fragments thereofwhich immunospecifically bind to one or more RSV antigens and have anaffinity constant or K_(a) (k_(on)/k_(off)) of at least 10² M⁻¹, atleast 5×10² M⁻¹, at least 10³ M⁻¹, at least 5×10³ M⁻¹, at least 10⁴ M⁻¹,at least 5×10⁴ M⁻¹, at least 10⁵ M⁻¹, at least 5×10⁵ M⁻¹, at least 10⁶M⁻¹, at least 5×10⁶ M⁻¹, at least 10⁷ M⁻¹, at least 5×10⁷M⁻¹, at least10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, atleast 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹M⁻¹, at least 10¹² M⁻¹, at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹, at least5×10¹³ M⁻¹, at least 10¹⁴ M⁻¹, at least 5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹,or at least 5×10¹⁵ M⁻¹. In particular, the present invention providescompositions for use in the prevention, treatment or amelioration of oneor more symptoms associated with a RSV infection, said compositionscomprising one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens and have a K_(a) ofat least 10² M⁻¹, at least 5×10² M⁻¹, at least 10³ M⁻¹, at least 5×03M⁻¹, at least 10⁴ M⁻¹, at least 5×10⁴ M⁻¹ at least 5×10⁵ M⁻¹, at least5×10⁵ M⁻¹, at least 10⁶ M⁻¹, at least 5×10⁶ M⁻¹, at least 10⁷ M⁻¹, atleast 5×10⁷M⁻¹, at least 10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹,at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹, at least 5×10¹² M⁻¹,at least 10¹³ M⁻¹, at least 5×10¹³ M⁻¹, at least 10¹⁴ M⁻¹, at least5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹, or at least 5×10¹⁵ M⁻¹.

The present invention provides antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens and have a medianeffective concentration (EC₅₀) of less than 0.01 nM, less than 0.025 nM,less than 0.05 nM, less than 0.1 nM, less than 0.25 nM, less than 0.5nM, less than 0.75 nM, less than 1 nM, less than 1.25 nM, less than 1.5nM, less than 1.75 nM, or less than 2 nM, in an in vitromicroneutralization assay. In particular, the present invention providescompositions for use in the prevention, treatment or amelioration of oneor more symptoms associated with a RSV infection, said compositionscomprising one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens and have an EC₅₀ ofless than 0.01 nM, less than 0.025 nM, less than 0.05 nM, less than 0.1nM, less than 0.25 nM, less than 0.5 nM, less than 0.75 nM, less than 1nM, less than 1.25 nM, less than 1.5 nM, less than 1.75 nM, or less than2 nM, in an in vitro microneutralization assay

The present invention also provides antibodies or fragments thereofcomprising a VH domain having the amino acid sequence of any VH domainlisted in Table 2 and compositions comprising said antibodies orantibody fragments for use in the prevention, treatment or ameliorationof one or more symptoms associated with a RSV infection. The presentinvention also provides antibodies or fragments thereof comprising oneor more VH complementarity determining regions (CDRS) having the aminoacid sequence of one or ore VH CDRs listed in Table 2 and/or Table 3 andcompositions comprising said antibodies or antibody fragments for use inthe prevention, treatment or amelioration of one or more symptomsassociated with a RSV infection. The present invention also providesantibodies or fragments thereof comprising a VL domain having the aminoacid sequence of any VL domain listed in Table 2. The present inventionalso provides antibodies or fragments thereof comprising one or more VLCDRs having the amino acid sequence of one or more VL CDRs listed inTable 2 and/or Table 3 and compositions comprising said antibodies orantibody fragments for use in the prevention, treatment or ameliorationof one or more symptoms associated with a RSV infection. The presentinvention further provides antibodies comprising a VH domain and a VLdomain having the amino acid sequence of any VH domain and VL domainlisted in Table 2 and compositions comprising said antibodies orantibody fragments for use in the prevention, treatment or ameliorationof one or more symptoms associated with a RSV infection. The presentinvention further provides antibodies comprising one or more VH CDRs andone or more VL CDRs having the amino acid sequence of one or more VHCDRs and one or more VL CDRs listed in Table 2 and/or 3 and compositionscomprising said antibodies or antibody fragments for use in theprevention, treatment or amelioration of one or more symptoms associatedwith a RSV infection. In the above embodiments, preferably the antibodybinds immunospecifically to a RSV antigen.

The present invention also encompasses methods for achieving a serumtiter of at least 40 μg/ml of one or more antibodies or fragmentsthereof that immunospecifically bind to one or more RSV antigens in amammal, preferably a primate and most preferably a human. In particular,the present invention provides methods for achieving a serum titer of atleast 40 μg/ml (preferably at least 75 μg/ml, more preferably at least100 μg/ml, and most preferably at least 150 μg/ml) of an antibody orfragment thereof that immunospecifically binds to a RSV antigen in anon-primate mammal, comprising administering a dose of less than 2.5mg/kg (preferably 1.5 mg/kg or less) of the antibody or antibodyfragment to the non-primate mammal and measuring the serum titer of theantibody or antibody fragment at least 1 day after administering thedose to the non-primate mammal. The present invention also providesmethods for achieving a serum titer of at least 150 μg/ml (preferably atleast 200 μg/ml) of an antibody or fragment thereof thatimmunospecifically binds to a RSV antigen in a non-primate mammal,comprising administering a dose of approximately 5 mg/kg of the antibodyor antibody fragment to the non-primate mammal and measuring the serumtiter of the antibody or antibody fragment at least 1 day after theadministration of the dose to the non-primate mammal.

The present invention also provides methods for achieving a serum titerof at least 40 μg/ml of an antibody or fragment thereof thatimmunospecifically binds to a RSV antigen in a primate, comprisingadministering a first dose of 10 mg/kg (preferably 5 mg/kg or less andmore preferably 1.5 mg/kg or less) of the antibody or antibody fragmentto the primate and measuring the serum titer of the antibody or antibodyfragment 20 days (preferably 25, 30, 35 or 40 days) after administratingthe first dose to the primate and prior to the administration of anysubsequent dose. The present invention also provides methods forachieving a serum titer of at least 75 μg/ml (preferably at least 100μg/ml, at least 150 μg/ml, or at least 200 μg/ml) of an antibody orfragment thereof that immunospecifically binds to a RSV antigen in aprimate, comprising administering a first dose of approximately 15 mg/kgof the antibody or antibody fragment to the primate and measuring theserum titer of the antibody or antibody fragment 20 days (preferably 25,30, 35 or 40 days) after administering the first dose to the primate butprior to any subsequent dose.

The present invention also provides methods for preventing, treating, orameliorating one or more symptoms associated with a RSV infection in ahuman subject, said methods comprising administering to said humansubject at least a first dose of approximately 15 mg/kg of an antibodyor fragment thereof that immunospecifically binds to a RSV antigen sothat said human subject has a serum antibody titer of at least 75 μg/ml,preferably at least 100 μg/ml, at least 150 μg/ml, or at least 200 μg/ml30 days after the administration of the first dose of the antibody orantibody fragment and prior to the administration of a subsequent dose.The present invention also provides methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in ahuman subject, said methods comprising administering to said humansubject at least a first dose of less than 15 mg/kg (preferably 10 mg/kgor less, more preferably 5 mg/kg or less, and most preferably 1.5 mg/kgor less) of an antibody or fragment thereof that immunospecificallybinds to a RSV antigen so that said human subject has a serum antibodytiter of at least 75 μg/ml, preferably at least 100 μg/ml, at least 150μg/ml, or at least 200 μg/ml 30 days after the administration of thefirst dose of the antibody or antibody fragment and prior to theadministration of a subsequent dose. The present invention furtherprovides methods for preventing, treating or ameliorating one or moresymptoms associated with a RSV infection in a human subject, saidmethods comprising administering to said human subject a first dose ofan antibody or fragment thereof that immunospecifically binds to a RSVantigen such that a prophylactically or therapeutically effective serumtiter of less than 10 μg/ml is achieved no more than 30 days afteradministering the antibody or antibody fragment.

The present invention provides methods for achieving a therapeuticallyor prophylactically effective serum titer in a mammal, said methodscomprising administering to said mammal an antibody or fragment thereofwhich immunospecifically binds to a RSV antigen and which has a k_(on)rate

$\left( {{{{antibody}\mspace{14mu}({Ab})} + {{antigen}\mspace{14mu}({Ag})}}\overset{k_{on}}{\rightarrow}{{Ab} - {Ag}}} \right)$of at least 2.5×10⁻⁵M⁻¹ s′, preferably at least 3×10⁵M⁻¹ s⁻¹, at least5×10⁵M⁻¹ s⁻¹, at least 10⁶M⁻¹ s⁻¹, at least 5×10⁶M⁻¹ s⁻¹, at least10⁷M⁻¹ s⁻¹, at least 5×10⁷M⁻¹ s⁻¹ or at least 10⁸M⁻¹ s⁻¹. In particular,the present invention provides methods for achieving a therapeuticallyor prophylactically effective serum titer, wherein said effective serumtiter is less than 30 μg/ml (and is preferably at least 0.2 μg/ml, morepreferably at least 4 μg/ml, and most preferably at least 6 μg/ml) aftera certain number of days (for example, but not limited to, 20, 25, 30 or35 days) without any other dosing within that period, comprisingadministering to a mammal an antibody or fragment thereof whichimmunospecifically binds to a RSV antigen and which has a k_(on) rate ofat least 2.5×10⁵ M⁻¹s⁻¹, preferably at least 3×10⁵ M⁻¹s⁻¹, at least5×10⁵ M⁻¹s⁻¹, at least 10⁶ M⁻¹s⁻¹, at least 5×10⁶ M⁻¹s⁻¹, at least 10⁷M⁻¹s⁻¹, at least 5×10⁷ M⁻¹s⁻¹, or at least 10⁸ M⁻¹s⁻¹. Preferably, theantibody or antibody fragment has a higher k_(on), rate than SYNAGIS®.

The present invention also provides methods of neutralizing RSV using anantibody or fragment thereof which immunospecifically bind to a RSVantigen and which has a k_(on) rate of at least 2.5×10⁵ M⁻¹s⁻¹,preferably at least 3×10⁵ M⁻¹s⁻¹, at least 5×10⁵ M⁻¹s⁻¹, at least 10⁶M⁻¹s⁻¹, at least 5×10⁶ M⁻¹s⁻¹, at least 10⁷ M⁻¹s⁻¹, at least 5×10⁷M⁻¹s⁻¹, or at least 10 ⁸ M⁻¹s⁻¹ to achieve a prophylactically ortherapeutically effective serum titer, wherein said effective serumtiter is less than 30 μg/ml (and is preferably at least 2 μg/ml, morepreferably at least 4 μg/ml, and most preferably at least 6 μg/ml) 20,25, 30, or 35 days after administration without any other dosageadministration. Preferably, the antibody or antibody fragment has ahigher k_(on) rate than SYNAGIS®.

The present invention also provides methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in amammal, preferably a human, said methods comprising administering tosaid mammal, a dose of less than 15 mg/kg (preferably 5 mg/kg or less,more preferably 3 mg/kg or less, and most preferably 1.5 mg/kg or less)of an antibody or fragment thereof which immunospecifically binds to aRSV antigen and has a k_(on) rate of at least 2.5×10⁵ M⁻¹s⁻¹, preferablyat least 3×10⁵ M⁻¹s⁻¹, at least 5×10⁵M⁻¹s⁻¹, at least 10⁶ M⁻¹s⁻¹, atleast 5×10⁶M⁻¹s⁻¹, at least 10⁷ M⁻¹s⁻¹, at least 5×10⁷ M⁻¹s⁻¹, or atleast 10⁸ M⁻¹s⁻¹. Preferably, the antibody or antibody fragment has ahigher k_(on) rate for the RSV F glycoprotein than SYNAGIS®.

The present invention also provides methods for achieving atherapeutically or prophylactically effective serum titer in a mammal,said methods comprising administering to said mammal an antibody orfragment thereof which immunospecifically binds to a RSV antigen andwhich has a K_(off) rate

$\left( {{{{antibody}\mspace{14mu}({Ab})} + {{antigen}\mspace{14mu}({Ag})}}\overset{K_{off}}{\leftarrow}{{Ab} - {Ag}}} \right)$of less than 6.5×10⁻⁴ sec⁻¹, less than 5×10⁻⁴ sec¹, less than 3×10⁻⁴sec⁻¹, less than 2×10⁻⁴ sec⁻¹, less than 1×10⁻⁴ sec⁻¹, or less than5×10⁻³ sec⁻¹. In particular, the present invention provides methods forachieving a therapeutically or prophylactically effective serum titer,wherein said effective serum titer is less than 30 μg/ml (and ispreferably at least 2 μg/ml, more preferably at least 4 μg/ml, and mostpreferably at least 6 μg/ml) after a certain number of days (forexample, but not limited to, 20, 25, 30 or 35 days) without any otherdosing within that period, comprising administering to a mammal anantibody or fragment thereof which immunospecifically binds to a RSVantigen and which has a K_(off) rate of less than 6.5×10⁻⁴ sec⁻¹, lessthan 5×10⁻⁴ sec⁻¹, less than 3×10⁻⁴ sec⁻¹, less than 2×10⁻⁴ sec⁻¹, lessthan 1×10⁻⁴ sec¹, or less than 3×10⁻³ sec⁻¹. Preferably, the antibody orfragment thereof has a lower K_(off) rate than SYNAGIS®.

The present invention also provides methods of neutralizing RSV using anantibody or antibody fragment thereof which immunospecifically binds toa RSV antigen and which has a K_(off) rate of less than 6.5×10⁻⁴ sec⁻¹,less than 5×10⁻⁴ sec⁻¹, less than 3×10⁻⁴ sec⁻¹, less than 2×10⁻⁴ sec⁻¹,less than 1×10⁻⁴ sec⁻¹, or less than 5×10⁻³ sec⁻¹ to achieve aprophylactically or therapeutically effective serum titer, wherein saideffective serum titer is less than 30 μg/ml (and is preferably at least2 μg/ml, more preferably at least 4 μg/ml, and most preferably at least6 μg/ml) 20, 25, 30, or 35 days after administration without any otherdosage administration. Preferably, the antibody or antibody fragment hasa lower K_(off) than SYNAGIS®.

The present invention also provides methods for preventing, treating, orameliorating one or more symptoms associated with a RSV infection in amammal, preferably a human, said methods comprising administering to asaid mammal a dose of less than 15 mg/kg (preferably 5 mg/kg or less,more preferably 3 mg/kg or less, and most preferably 1.5 mg/kg or less)of an antibody or a fragment thereof which immunospecifically binds to aRSV antigen and which has a K_(off) rate of less than 6.5×10⁻⁴ sec⁻¹,less than 5×10⁻⁴ sec⁻¹, less than 3×10⁻⁴ sec⁻¹, less than 2×10⁻⁴ sec⁻¹,less than 1×10⁻⁴ sec⁻¹, or less than 5×10⁻³ sec⁻¹. Preferably, theantibody or antibody fragment has a lower K_(off) rate than SYNAGIS®.

The present invention also provides methods for achieving atherapeutically or prophylactically effective serum titer in a mammal,said methods comprising administering to said mammal an antibody orfragment thereof which immunospecifically binds to a RSV antigen andwhich has an EC₅₀ of less than 0.01 nM, less than 0.025 nM, less than0.05 nM, less than 0.1 nM, less than 0.25 nM, less than 0.5 nM, lessthan 0.75 nM, less than 1 nM, less than 1.25 nM, less than 1.5 nM, lessthan 1.75 nM, or less than 2 nM, in an in vitro microneutralizationassay. In particular, the present invention provides methods forachieving a therapeutically or prophylactically effective serum titer,wherein said effective serum titer is less than 30 μg/ml (and ispreferably at least 2 μg/ml, more preferably at least 4 μg/ml, and mostpreferably at least 6 μg/ml) after a certain number of days (forexample, but not limited to, 20, 25, 30 or 35 days) without any otherdosing within that period, comprising administering to a mammal anantibody or fragment thereof which immunospecifically binds to a RSVantigen and which has an EC₅₀ of less than 0.01 nM, less than 0.025 nM,less than 0.05 nM, less than 0.1 nM, less than 0.25 nM, less than 0.5nM, less than 0.75 nM, less than 1 nM, less than 1.25 nM, less than 1.5nM, less than 1.75 nM, or less than 2 nM, in an in vitromicroneutralization assay Preferably, the antibody or antibody fragmenthas a lower EC₅₀ than SYNAGIS®.

The present invention also provides methods of neutralizing RSV using anantibody or fragment thereof which immunospecifically binds to a RSVantigen and which has an EC₅₀ of less than 0.01 nM, less than 0.025 nM,less than 0.05 nM, less than 0.1 nM, less than 0.25 nM, less than 0.5nM, less than 0.75 nM, less than 1 nM, less than 1.25 nM, less than 1.5nM, less than 1.75 nM, or less than 2 nM, in an in vitromicroneutralization assay to achieve a prophylactically ortherapeutically effective serum titer, wherein said effective serumtiter is less than 30 μg/ml (and is preferably at least 2 μg/ml, morepreferably at least 4 μg/ml, and most preferably at least 6 μg/ml) 20,25, 30, or 35 days after administration without any other dosageadministration. Preferably, the antibody or antibody fragment has alower EC₅₀ than SYNAGIS®.

The present invention also provides methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in amammal, preferably a human, said methods comprising administering tosaid mammal a dose of less than 15 mg/kg (preferably 5 mg/kg or less,more preferably 3 mg/kg or less, and most preferably 1.5 mg/kg or less)of an antibody or a fragment thereof which immunospecifically binds to aRSV antigen and which has an EC₅₀ of less than 0.01 nM, less than 0.025nM, less than 0.05 nM, less than 0.1 nM, less than 0.25 mM, less than0.5 nM, less than 0.75 nM, less than 1 nM, less than 1.25 nM, less than1.5 nM, less than 1.75 nM, or less than 2 nM, in an in vitromicroneutralization assay. Preferably, the antibody or antibody fragmenthas a lower EC₅₀ than SYNAGIS®.

The present invention provides methods for achieving a therapeuticallyor prophylactically effective serum titer in a mammal, said methodscomprising administering to said mammal an antibody or fragment thereofwhich immunospecifically binds to a RSV antigen and which has anaffinity constant (K_(a)) for a RSV antigen of at least 2×10⁸ M⁻¹, atleast 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, atleast 10¹² M⁻¹, at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹, at least 5×10¹³M⁻¹, at least 10¹⁴ M⁻¹, at least 5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹, or atleast 5×10¹⁵ M⁻¹. In particular, the present invention also providesmethods for achieving a therapeutically or prophylactically effectiveserum titer, wherein said effective serum titer is less than 30 μg/ml(and is preferably at least 2 μg/ml, more preferably at least 4 μg/ml,and most preferably at least 6 μg/ml) after a certain number of days(for example, but not limited to, 20, 25, 30 or 35 days) without anyother dosing within that period, comprising administering to a mammal anantibody or fragment thereof that has an affinity constant (K_(a)) for aRSV antigen of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹,at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹, at least 5×10¹³ M⁻¹, at least10¹⁴ M⁻¹, at least 5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹, or at least 5×10¹⁵M⁻¹. Preferably, the antibody or antibody fragment has a higher affinityfor a RSV F glycoprotein than SYNAGIS®.

The present invention also provides methods of achieving atherapeutically or prophylactically effective serum titer, wherein saideffective serum titer is less than 30 μg/ml (and is preferably at least2 μg/ml, more preferably at least 4 μg/ml, and most preferably at least6 μg/ml) after a certain number of days (for example, but not limitedto, 20, 25, 30 or 35 days) without any other dosing within that period,comprising administering to a mammal an antibody or fragment thereofwhich immunospecifically binds to a RSV antigen with a higher aviditythan known antibodies such as, e.g., SYNAGIS®.

The present invention also provides methods of neutralizing RSV using anantibody or fragment thereof that has an affinity constant (K_(a)) for aRSV antigen of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹,at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹, at least 5×10¹³ M⁻¹, at least10¹⁴ M⁻¹, at least 5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹, or at least 5×10¹⁵ M⁻¹to achieve a prophylactically or therapeutically effective serum titer,wherein said effective serum titer is less than 30 μg/ml (and is atleast 2 μg/ml and more preferably at least 6 μg/ml) 20, 25, 30, or 35days after administration without any other dosage administration.Preferably, the antibody or antibody fragment has a higher affinity forthe RSV F glycoprotein than SYNAGIS®. The present invention alsoprovides methods of neutralizing RSV using an antibody or fragmentthereof that has a higher avidity than known antibodies such as, e.g.,SYNAGIS®.

The present invention also provides methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in amammal, preferably a human, said methods comprising administering tosaid mammal a dose of less than 15 mg/kg (preferably 5 mg/kg or less,more preferably 3 mg/kg or less, and most preferably 1.5 mg/kg or less)of an antibody or fragment thereof that has an affinity constant (K_(a))for a RSV antigen of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, atleast 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹²M⁻¹, at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹, at least 5×10¹³ M, at least10¹⁴ M⁻¹, at least 5×10¹⁴ M¹, at least 10¹⁵ M⁻¹, or at least 5×10¹⁵ M⁻¹.Preferably, the antibody or antibody fragment has a higher affinity forthe RSV F glycoprotein than SYNAGIS®. The present invention alsoprovides methods for preventing, treating or ameliorating one or moresymptoms associated with a RSV infection in a mammal, preferably ahuman, said methods comprising administering to said mammal a first doseof less than 15 mg/kg (preferably 5 mg/kg or less, more preferably 3mg/kg or less, and most preferably 1.5 mg/kg or less) of an antibody orfragment thereof that has a higher avidity than known antibodies suchas, e.g., SYNAGIS®.

The present invention encompasses methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in amammal, preferably a human, comprising administering to said mammal afirst dose of a prophylactically or therapeutically effective amount ofone or more antibodies or fragments thereof that immunospecifically bindto one or more RSV antigens with higher avidity and/or higher affinitythan known antibodies such as, e.g., SYNAGIS®, wherein said effectiveamount is less than 15 mg/kg (preferably 5 mg/kg or less, morepreferably 3 mg/kg or less, and most preferably 1.5 mg/kg or less) ofsaid antibodies or antibody fragments which dose results in a serumtiter of less than 30 μg/ml (which is preferably at least 2 μg/ml, morepreferably at least 4 μg/ml, and most preferably at least 6 μg/ml) atleast 20 days (preferably at least 25, at least 30, or at least 35 days)after the administration of the first dose and prior to theadministration of a subsequent dose. In particular, the presentinvention provides methods for preventing, treating, or ameliorating oneor more symptoms associated with a RSV infection in a human subject,comprising administering to said human subject a first dose of less than5 mg/kg (preferably 3 mg/kg or less, and most preferably 1.5 mg/kg) ofan antibody or fragment thereof that immunospecifically binds to a RSVantigen with higher avidity and/or higher affinity than known antibodiessuch as, e.g., SYNAGISO® (e.g., an affinity of at least 2×10⁸ M⁻¹, atleast 2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least5×10¹¹ M⁻¹, at least 10¹² M⁻¹, or at least 5×10¹² M⁻¹) so that saidhuman subject has a serum antibody titer of less than 30 μg/ml (which ispreferably at least 2 μg/ml, more preferably at least 4 μg/ml, and mostpreferably at least 6 μg/ml) at least 20 days (preferably at least 25,at least 30, or at least 35 days) after the administration of the firstdose of the antibody or antibody fragment and prior to theadministration of a subsequent dose.

The present invention also provides methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in amammal, said methods comprising administering to said mammal a firstdose of one or more antibodies or fragments thereof comprising a VHdomain having an amino acid sequence of any VH domain listed in Table 2to achieve a therapeutically or prophylactically effective serum titer,wherein said effective serum titer is less than 30 μg/ml (and ispreferably at least 2 μg/ml, more preferably at least 4 μg/ml, and mostpreferably at least 6 μg/ml) after a certain number of days (forexample, but not limited to, 20, 25, 30 or 35 days) without any otherdosing within that period. The present invention also provides methodsfor preventing, treating or ameliorating one or more symptoms associatedwith a RSV infection in a mammal, said methods comprising administeringto said mammal a first dose of one or more antibodies or fragmentsthereof comprising one or more VH complementarity determining regions(CDRs) having the amino acid sequence of one or more VH CDRs listed inTable 2 and/or Table 3 to achieve a therapeutically or prophylacticallyeffective serum titer, wherein said effective serum titer is less than30 μg/ml (and is preferably at least 2 μg/ml, more preferably at least 4μg/ml, and most preferably at least 6 μg/ml) after a certain number ofdays (for example, but not limited to, 20, 25, 30 or 35 days) withoutany other dosing within that period. Preferably, said antibodies orantibody fragments immunospecifically bind to a RSV antigen.

The present invention also provides methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in amammal, said methods comprising administering to said mammal a firstdose of one or more antibodies or fragments thereof comprising a VLdomain having the amino acid sequence of any VL domain listed in Table 2to achieve a therapeutically or prophylactically effective serum titer,wherein said effective serum titer is less than 30 μg/ml (and ispreferably at least 2 μg/ml, more preferably at least 4 μg/ml, and mostpreferably at least 6 μg/ml) after a certain number of days (forexample, but not limited to, 20, 25, 30 or 35 days) without any otherdosing within that period. The present invention also provides methodsfor preventing, treating or ameliorating one or more symptoms associatedwith a RSV infection in a mammal, said methods comprising administeringto said mammal a first dose of one or more antibodies or fragmentsthereof comprising one or more VL CDRs having the amino acid sequence ofone or more VL CDRs listed in Table 2 and/or Table 3 to achieve atherapeutically or prophylactically effective serum titer, wherein saideffective serum titer is less than 30 μg/ml (and is preferably at least2 μg/ml, more preferably at least 4 μg/ml, and most preferably at least6 μg/ml) after a certain number of days (for example, but not limitedto, 20, 25, 30 or 35 days) without any other dosing within that period.Preferably, said antibodies or antibody fragments immunospecificallybind to a RSV antigen.

The present invention also provides methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in amammal, said methods comprising administering to said mammal a firstdose of one or more antibodies or fragments thereof comprising a VHdomain and a VL domain having the amino acid sequence of any VH domainand VL domain listed in Table 2 to achieve a therapeutically orprophylactically effective serum titer, wherein said effective serumtiter is less than 30 μg/ml (and is preferably at least 2 μg/ml, morepreferably at least 4 μg/ml, and most preferably at least 6 μg/ml) aftera certain number of days (for example, but not limited to, 20, 25, 30 or35 days) without any other dosing within that period. The presentinvention also provides methods for preventing, treating or amelioratingone or more symptoms associated with a RSV infection in a mammal, saidmethods comprising administering to said mammal a first dose of one ormore antibodies or fragments thereof comprising one or more VH CDRs andone or more VL CDRs having the amino acid sequence of one or more VHCDRs and one or more VL CDRs listed in Table 2 and/or 3 to achieve atherapeutically or prophylactically effective serum titer, wherein saideffective serum titer is less than 30 μg/ml (and is preferably at least2 μg/ml, more preferably at least 4 μg/ml, and most preferably at least6 μg/ml) after a certain number of days (for example, but not limitedto, 20, 25, 30 or 35 days) without any other dosing within that period.Preferably, said antibodies or antibody fragments immunospecificallybind to a RSV antigen.

In a specific embodiment, the present invention provides methods forpreventing, treating or ameliorating one or more symptoms associatedwith a RSV infection in a mammal, said methods comprising administeringto said mammal a first dose of one or more antibodies or fragmentsthereof comprising a VH domain having an amino acid sequence of SEQ IDNO:7, 9, 17, 24, 28, 33, 36, 40, 44, 48, 51, 67, or 78 and/or a VLdomain having an amino acid sequence of SEQ ID NO:8, 11, 13, 21, 26, 30,34, 38, 42, 46, 49, 52, 54, 56, 58, 60, 62, 64, 65, 68, 70, 71, 74 or 76to achieve a therapeutically or prophylactically effective serum titer,wherein said effective serum titer is less than 30 μg/ml (and ispreferably at least 2 μg/ml, more preferably at least 4 μg/ml, and mostpreferably at least 6 μg/ml) after a certain number of days (forexample, but not limited to, 20, 25, 30 or 35 days) without any otherdosing within that period. In a preferred embodiment, the presentinvention provides methods for preventing, treating or ameliorating oneor more symptoms associated with a RSV infection in a mammal, saidmethods comprising administering to said mammal a first dose of one ormore antibodies or fragments thereof comprising a VH domain having anamino acid sequence of SEQ ID NO:9, 17, 24, 28, 33, 36, 40, 44, 48, 51,55, 67 or 78 and/or a VL domain having an amino acid sequence of SEQ IDNO:13, 21, 26, 30, 34, 38, 42, 46, 49, 52, 54, 56, 58, 60, 62, 64, 65,68, 70, 71, 74 or 76 to achieve a therapeutically or prophylacticallyeffective serum titer, wherein said effective serum titer is less than30 μg/ml (and is preferably at least 2 μg/ml, more preferably at least 4μg/ml, and most preferably at least 6 μg/ml) after a certain number ofdays (for example, but not limited to, 20, 25, 30 or 35 days) withoutany other dosing within that period. In another embodiment, the presentinvention provides methods for preventing, treating or ameliorating oneor more symptoms associated with a RSV infection in a mammal, saidmethods comprising administering to said mammal a first dose of one ormore antibodies or fragments thereof comprising a VH CDR3 having anamino acid sequence of SEQ ID NO:3, 12, 20, 29, or 79 and a VL CDR3having an amino acid sequence of SEQ ID NO:6, 16 or 61 to atherapeutically or prophylactically effective serum titer, wherein saideffective serum titer is less than 30 μg/ml (and is preferably at least2 μg/ml, more preferably at least 4 μg/ml, and most preferably at least6 μg/ml) after a certain number of days (for example, but not limitedto, 20, 25, 30 or 35 days) without any other dosing within that period.

The present invention also provides compositions comprising one or moreantibodies or fragments thereof which immunospecifically bind to one ormore RSV antigens and which have increased in vivo half-lives comparedto known anti-RSV antibodies as a result of, e.g., one or moremodifications in amino acid residues identified to be involved in theinteraction between the Fc domain of said antibodies or antibodyfragments and the FcRn receptor. In one embodiment, a composition of theinvention comprises HL-SYNAGIS or an antigen-binding fragment thereof.In another embodiment, a composition of the invention comprises one ormore antibodies or fragments thereof which immunospecifically bind toone or more RSV antigens with a higher avidity and/or a higher affinitythan known antibodies such as, e.g., SYNAGIS® (e.g., antibodies orantibody fragments with an affinity of at least 2×10⁸ M⁻¹, at least2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹,at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least5×10¹¹ M⁻¹, at least 10¹² M⁻¹, or at least 5×10¹² M⁻¹ for a RSV antigen)and which comprise an Fc domain with increased affinity for the FcRnreceptor relative to the Fc domain of SYNAGIS®. In accordance with thisembodiment, the increased affinity of the Fc domain of said antibodiesor antibody fragments results in an in vivo half-life of said antibodiesor antibody fragments of at least 25 days, preferably at least 30 days,more preferably at least 30 days, and most preferably at least 40 days.In another embodiment, a composition of the invention comprisesHL-SYNAGIS or an antigen-binding fragment thereof and one or moreantibodies or fragments thereof which immunospecifically bind to one ormore RSV antigens and which comprise an Fc domain with increasedaffinity for the FcRn receptor relative to the Fc domain of SYNAGIS®.

The present invention also provides compositions comprising one or morepegylated antibodies or fragments thereof which immunospecifically bindto one or more RSV antigens. In one embodiment, a composition of theinvention comprises pegylated SYNAGIS® or a fragment thereof. In anotherembodiment, a composition of the invention comprises one or morepegylated antibodies or fragments thereof that immunospecifically bindto one or more RSV antigens with higher avidity and/or higher affinitythan known antibodies such as, e.g., SYNAGIS®. In yet anotherembodiment, a composition of the invention comprises pegylated SYNAGIS®or an antigen-binding fragment thereof and one or more pegylatedantibodies or fragments thereof that immunospecifically bind to one ormore RSV antigens with higher avidity and/or higher affinity than knownantibodies such as, e.g., SYNAGIS®.

The present invention also provides compositions comprising one or morepegylated antibodies or fragments thereof which comprise an Fc domainwith increased affinity for the FcRn receptor relative to the Fc domainof SYNAGIS®. In one embodiment, a composition of the invention comprisesa pegylated HL-SYNAGIS or an antigen-binding fragment thereof. Inanother embodiment, a composition of the invention comprises one or morepegylated antibodies or fragments thereof which immunospecifically bindto one or more RSV antigens with a higher avidity and/or a higheraffinity than known such as, e.g., SYNAGIS® and which comprise an Fcdomain with increased affinity for the FcRn receptor relative to the Fcdomain of SYNAGIS®

The present invention encompasses methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in amammal, preferably a human, comprising administering to said mammal afirst dose of a prophylactically or therapeutically effective amount ofHL-SYNAGIS or an antigen-binding fragment thereof, wherein saideffective amount is approximately 15 mg/kg of said antibodies orfragments thereof which dose results in a serum titer of at least 30μg/ml at least 30 days after the administration of the first dose andprior to the administration of a subsequent dose. In particular, thepresent invention provides methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in ahuman subject, comprising administering to said human subject a firstdose of 15 mg/kg of HL-SYNAGIS or an antigen-binding fragment thereof sothat said human subject has a serum antibody titer of at least 30 μg/mlat least 30 days after the administration of the first dose of theantibody or antibody fragment and prior to the administration of asubsequent dose.

The present invention also encompasses methods for preventing, treatingor ameliorating one or more symptoms associated with a RSV infection ina mammal, preferably a human, comprising administering to said mammal afirst dose of a prophylactically or therapeutically effective amount ofone or more antibodies or fragments thereof which have increased in vivohalf-lives and which immunospecifically bind to one or more RSV antigenswith higher avidity and/or higher affinity than known antibodies suchas, e.g., SYNAGIS® (e.g., antibodies or antibody fragments with anaffinity of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M¹, orat least 5×10¹² M⁻¹ for a RSV antigen), wherein said effective amount isless than 15 mg/kg (preferably 5 mg/kg or less, more preferably 3 mg/kgor less, and most preferably 1.5 mg/kg or less) of said antibodies orfragments thereof which dose results in a serum titer of less than 30μg/ml (which is preferably at least 2 μg/ml, more preferably at least 4μg/ml, and most preferably at least 6 μg/ml) at least 20 days(preferably at least 25, at least 30, or at least 35 days) after theadministration of the first dose and prior to the administration of asubsequent dose. In particular, the present invention provides methodsfor preventing, treating or ameliorating one or more symptoms associatedwith a RSV infection in a human subject, comprising administering tosaid human subject a first dose of less than 5 mg/kg (preferably 1.5mg/kg or less) of an antibody or a fragment thereof which has anincreased in vivo half-life and which immunospecifically binds to a RSVantigen with higher avidity and/or higher affinity than known antibodiessuch as, e.g., SYNAGIS® (e.g., antibodies or antibody fragments with anaffinity of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹,or at least 5×10¹² M⁻¹ for a RSV antigen) so that said human subject hasa serum antibody titer of less than 30 μg/ml (which is preferably atleast 2 μg/ml, more preferably at least 4 μg/ml, and most preferably atleast 6 μg/ml) at least 25 days (preferably at least 30, at least 35, orat least 40 days) after the administration of the first dose of theantibody or antibody fragment and prior to the administration of asubsequent dose.

The present invention provides sustained release formulations comprisingone or more antibodies or fragments thereof that immunospecifically bindto one or more RSV antigens. In one embodiment, a sustained releaseformulation comprises SYNAGIS® or a fragment thereof. In anotherembodiment, a sustained release formulation comprises one or moreantibodies or fragments thereof that immunospecifically bind to one ormore RSV antigens with higher avidity and/or higher affinity than knownantibodies such as, e.g., SYNAGIS® (e.g., antibodies or antibodyfragments with an affinity of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹,at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10 1 M⁻¹, atleast 10¹² M⁻¹, or at least 5×10¹² M⁻¹ for a RSV antigen). In anotherembodiment, a sustained release formulation comprises SYNAGIS® or anantigen-binding fragment thereof and one or more antibodies or fragmentsthereof that immunospecifically bind to one or more RSV antigens withhigher avidity and/or higher affinity than known antibodies such as,e.g., SYNAGIS® (e.g., antibodies or antibody fragments with an affinityof at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, atleast 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹, or atleast 5×10¹² M⁻¹ for a RSV antigen). In another embodiment, HL-SYNAGISor an antigen-binding fragment thereof is formulated in as sustainedrelease formulation. In yet another embodiment, antibodies or fragmentsthereof which have higher avidity and/or higher affinity for one or moreRSV antigens than known antibodies such as, e.g., SYNAGIS® (e.g.,antibodies or antibody fragments with an affinity of at least 2×10⁸ M⁻¹,at least 2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, atleast 5×10¹¹ M⁻¹, at least 10¹² M⁻¹, or at least 5×10¹² M⁻¹ for a RSVantigen) and which comprises an Fc domain with increased affinity forthe FcRn receptor relative to the Fc domain of SYNAGIS® are formulatedin sustained release formulations.

The present invention also provides methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection in amammal, preferably a human, comprising administering to said mammal afirst dose of a prophylactically or therapeutically effective amount ofone or more antibodies or fragments thereof that immunospecifically bindto one or more RSV antigens in a sustained release formulation, whereinsaid effective amount is a dose of 15 mg/kg or less of said antibodiesor fragments thereof, which dose, preferably results in a serum titer ofat least 2 μg/ml (preferably at least 5 μg/ml, at least 10 μg/ml, atleast 20 μg/ml, at least 30 μg/ml, or at least 40 μg/ml) for at least 20days (preferably at least 25, 30, 35 or 40 days) after theadministration of the first dose and prior to the administration of asubsequent dose.

In one embodiment, a mammal, preferably a human, is administered a firstdose of a prophylactically or therapeutically effective amount ofSYNAGIS® or an antigen-binding fragment thereof in a sustained releaseformulation, wherein said effective amount is a dose of approximately 15mg/kg of SYNAGIS® or an antigen-binding fragment thereof which doseresults in a serum titer of at least 20 μg/ml (preferably at least 30μg/ml, more preferably at least 40 μg/ml, and most preferably at least50 μg/ml) for at least 30 days (preferably at least 35 days, morepreferably at least 40 days, and most preferably at least 45 days) afterthe administration of the first dose and prior to the administration ofa subsequent dose. In a preferred embodiment, a mammal, preferably ahuman, is administered a first dose of a prophylactically ortherapeutically effective amount of SYNAGIS® or an antigen-bindingfragment thereof in a sustained release formulation, wherein saideffective amount is a dose of 15 mg/kg or less of SYNAGIS® or anantigen-binding fragment thereof which dose results in a serum titer of20 μg/ml (preferably at least 30 μg/ml, more preferably at least 40μg/ml, and most preferably at least 50 μg/ml) at least 30 days(preferably at least 35 days, more preferably at least 40 days, and mostpreferably at least 45 days) after the administration of the first doseand prior to the administration of a subsequent dose.

In another embodiment, a mammal, preferably a human, is administered afirst dose of a prophylactically or therapeutically effective amount ofone or more antibodies or fragments thereof which immunospecificallybind to one or more RSV antigens with higher avidity and/or higheraffinity than known antibodies such as, e.g., SYNAGIS® (e.g., antibodiesor antibody fragments with an affinity of at least 2×10⁸ M⁻¹, at least2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹,at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least5×10¹¹ M⁻¹, at least 10¹² M⁻¹, or at least 5×10¹² M⁻¹ for a RSV antigen)in a sustained release formulation, wherein said effective amount is adose of less than 15 mg/kg (preferably 5 mg/kg or less, more preferably3 mg/kg or less, and most preferably 1.5 mg/kg or less) of saidantibodies or antibody fragments which dose results in a serum titer ofless than 30 μg/ml (which is preferably at least 2 μg/ml, morepreferably at least 4 μg/ml, and most preferably at least 6 μg/ml) forat least 20 days (preferably at least 25, at least 30, at least 35, orat least 40 days) after the administration of the first dose and priorto the administration of a subsequent dose. In a preferred embodiment, amammal, preferably a human, is administered a first dose of aprophylactically or therapeutically effective amount of one or moreantibodies or fragments thereof which immunospecifically bind to one ormore RSV antigens with higher avidity and/or higher affinity than knownantibodies such as, e.g., SYNAGIS® (e.g., antibodies or antibodyfragments with an affinity of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹,at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, atleast 10¹² M⁻¹, or at least 5×10¹² M⁻¹ for a RSV antigen) in a sustainedrelease formulation, wherein said effective amount is a dose of lessthan 15 mg/kg of said antibodies or antibody fragments which doseresults in a serum titer of 10 μg/ml for at least 20 days (preferably atleast 25, at least 30, at least 35 or at least 40 days) after theadministration of the first dose and prior to the administration of asubsequent dose. In accordance with this embodiment, theprophylactically or therapeutically effective amount of the dose of theantibodies or antibody fragments is approximately 0.5 mg/kg, preferably1 mg/kg, 1.5 mg/kg, 3 mg/kg, 5 mg/kg, 7.5 mg/kg, 10 mg/kg, 12 mg/kg, or14 mg/kg. In another preferred embodiment, a mammal, preferably a human,is administered a first dose of a prophylactically or therapeuticallyeffective amount of one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens with higher avidityand/or higher affinity than known antibodies such as, e.g., SYNAGIS®(e.g., antibodies or antibody fragments with an affinity of at least2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹,at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹, or at least 5×10¹² M⁻¹for a RSV antigen) in a sustained release formulation, wherein saideffective amount is a dose of 1.5 mg/kg of said antibodies or antibodyfragments which dose results in a serum titer of 10 μg/ml for at least20 days (preferably at least 25, at least 30, at least 35, or at least40 days) after the administration of the first dose and prior to theadministration of a subsequent dose.

Additionally, the present invention provides sustained releasecompositions comprising one or more antibodies or fragments thereofwhich immunospecifically bind to one or more RSV antigens, whichsustained release compositions maintain a certain serum titer in asubject for a certain period of time without exceeding a particularserum titer. In one embodiment, a sustained release formulationcomprising SYNAGIS® or an antigen-binding fragment thereof maintains aserum titer in a mammal, preferably a human, of approximately 25 μg/ml(preferably 30 μg/ml, more preferably 40 μg/ml, and most preferably 50μg/ml) without exceeding a serum titer of approximately 100 μg/ml(preferably 75 μg/ml) for at least 20 days (preferably at least 25, 30,35, or 40 days). In another embodiment, a sustained release formulationcomprising one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens with a higheravidity and/or a higher affinity than previously known antibodies suchas, e.g., SYNAGIS®, maintains a serum titer in a mammal, preferably ahuman, of approximately 2 μg/ml (preferably 6 μg/ml, 10 μg/ml, 20 μg/ml,or 30 μg/ml) without exceeding a serum titer of approximately 40 μg/ml(preferably 75 μg/ml) for at least 20 days (preferably at least 25, 30,35, or 40 days).

The present invention encompasses methods of preventing, treating orameliorating one or more symptoms of RSV infection in a mammal,preferably a human, by administering sustained release formulations ofone or more antibodies or fragments thereof which immunospecificallybind to one or more RSV antigens and which have increased in vivohalf-lives. In one embodiment, a sustained release formulationcomprising HL-SYNAGIS or an antigen-binding fragment thereof isadministered to a mammal, preferably a human, to prevent, treat, orameliorate one or more symptoms associated with a RSV infection. Inanother embodiment, a sustained release formulation comprising one ormore antibodies or fragments thereof which have higher avidity and/orhigher affinity for one or more RSV antigens than known antibodies suchas, e.g., SYNAGIS® (e.g., antibodies or antibody fragments with anaffinity of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least5×10¹⁰ M⁻¹, at least 10¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹, orat least 5×10¹² M⁻¹ for a RSV antigen) and which comprises an Fc domainwith increased affinity for the FcRn receptor relative to the Fc domainof SYNAGIS® are administered to a mammal, preferably a human, toprevent, treat, or ameliorate one or more symptoms associated with a RSVinfection.

The present invention also provides pulmonary delivery systems foradministering one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens. In particular, thepresent invention provides compositions for pulmonary delivery, saidcompositions comprising one or more antibodies or fragments thereofwhich immunospecifically bind to one or more RSV antigens. SYNAGIS® oran antigen-binding fragment thereof can be incorporated intocompositions for pulmonary delivery. HL-SYNAGIS or an antigen-bindingfragment thereof can be incorporated into compositions for pulmonarydelivery. One or more antibodies or fragments thereof that bind to oneor more RSV antigens with higher affinity and/or higher avidity thanknown antibodies such as, e.g., SYNAGIS® (e.g., antibodies or antibodyfragments with an affinity of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹,at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, atleast 10¹² M⁻¹, or at least 5×10¹² M⁻¹ for a RSV antigen) can beincorporated into compositions for pulmonary delivery. Further, one ormore antibodies or fragments thereof which bind to one or more RSVantigens with higher affinity and/or higher avidity than knownantibodies such as, e.g., SYNAGIS® (e.g., antibodies or antibodyfragments with an affinity of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹,at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10 1 M⁻¹, atleast 10¹² M⁻¹, or at least 5×10¹² M⁻¹ for a RSV antigen) and whichcomprise an Fc domain with increased affinity for the FcRn receptorrelative to the Fc domain of SYNAGIS® can be incorporated intocompositions for pulmonary delivery.

The present invention also provides methods for preventing, treating orameliorating one or more symptoms associated with a RSV infection, saidmethods comprising administering to a mammal, preferably a human, acomposition for pulmonary delivery comprising one or more antibodies orfragments thereof which immunospecifically bind to one or more RSVantigens. In particular, the present invention provides methods forpreventing, treating or ameliorating one or more symptoms associatedwith a RSV infection, said methods comprising administering to a mammal,preferably a human, a composition for pulmonary delivery comprisingSYNAGIS® or fragments thereof. The present invention also providesmethods for preventing, treating or ameliorating one or more symptomsassociated with a RSV infection, said methods comprising administeringto a mammal, preferably a human, a composition for pulmonary deliverycomprising one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens with higher affinityand/or higher avidity than known antibodies such as, e.g., SYNAGIS®(e.g., antibodies or antibody fragments having an affinity of at least2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹,at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹, or at least 5×10¹² M⁻¹for one or more RSV antigens).

In one embodiment, a first dose of a prophylactically or therapeuticallyeffective amount of a composition comprising SYNAGIS® or anantigen-binding fragment thereof is administered to the lungs of amammal, preferably a human, and results in an antibody concentration ofat least 20 ng per mg of lung protein (preferably at least 40 ng/mg, atleast 60 ng/mg, at least 80 ng/mg, at least 50 ng/mg, at least 75 ng/mg,at least 100 ng/mg, or at least 150 ng/mg) at least 20 days (preferablyat least 25, 30, 35 or 40 days) after the administration of the firstdose and prior to the administration of a subsequent dose. Preferably,the prophylactically or therapeutically effective amount is a dose ofapproximately 0.01 mg/kg, (preferably at least 0.1 mg/kg, at least 1mg/kg, at least 2 mg/kg, at least 4 mg/kg, at least 5 mg/kg or at least10 mg/kg) of SYNAGIS® or an antigen-binding fragment thereof.

In another embodiment, a first dose of a prophylactically ortherapeutically effective amount of a composition comprising one or moreantibodies or fragments thereof which immunospecifically bind to one ormore RSV antigens with higher affinity and/or higher avidity than knownantibodies such as, e.g., SYNAGIS®, (e.g., antibodies or antibodyfragments having an affinity of at least 2×10⁸ M⁻¹, at least 2.5×10⁸M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹,at least 10¹² M⁻¹, or at least 5×10¹² M⁻¹ for one or more RSV antigens)is administered to the lungs of a mammal, preferably a human and resultsin an antibody concentration of 20 ng per mg of lung protein (preferablyat least 40 ng/mg, at least 60 ng/mg, at least 80 ng/mg, at least 50ng/mg, at least 75 ng/mg, at least 100 ng/mg, or at least 150 ng/mg), atleast 200 ng/mg, at least 250 ng/mg, at least 500 ng/mg, at least 750ng/mg, at least 1 μg/mg, at least 2 μg/mg, at least 5 μg/mg, at least 10μg/mg, at least 15 μg/mg, or at least 25 μg/mg) at least 20 days(preferably at least 25, 30, 35 or 40 days) at least 20 days (preferablyat least 25, at least 30, at least 35 or at least 40 days after theadministration of the first dose and prior to the administration of asubsequent dose. Preferably, the prophylactically effective amount is adose of approximately 0.001 mg/kg, (preferably at least 0.005 mg/kg, atleast 0.01 mg/kg, at least 0.05 mg/kg, at least 0.1 mg/kg, at least 1mg/kg, at least 2 mg/kg, at least 4 mg/kg, at least 5 mg/kg or at least10 mg/kg) of said antibodies or antibody fragments.

The present invention further provides detectable or diagnosticcompositions comprising using antibodies or fragments thereof thatimmunospecifically bind to a RSV antigen, and methods for detecting ordiagnosing a RSV infection utilizing said compositions.

3.1. DEFINITIONS

The term “analog” as used herein refers to a polypeptide that possessesa similar or identical function as a RSV polypeptide, a fragment of aRSV polypeptide, an antibody, or antibody fragment but does notnecessarily comprise a similar or identical amino acid sequence of a RSVpolypeptide, a fragment of a RSV polypeptide, an antibody, or antibodyfragment, or possess a similar or identical structure of a RSVpolypeptide, a fragment of a RSV polypeptide, an antibody, or antibodyfragment. A polypeptide that has a similar amino acid sequence refers toa polypeptide that satisfies at least one of the following: (a) apolypeptide having an amino acid sequence that is at least 30%, at least35%, at least 40%, at least 45%, at least 50%, at least 55%, at least60%, at least 65%, at least 70%, at least 75%, at least 80%, at least85%, at least 90%, at least 95% or at least 99% identical to the aminoacid sequence of a RSV polypeptide, a fragment of a RSV polypeptide, anantibody, or antibody fragment described herein; (b) a polypeptideencoded by a nucleotide sequence that hybridizes under stringentconditions to a nucleotide sequence encoding a RSV polypeptide, afragment of a RSV polypeptide, an antibody, or antibody fragmentdescribed herein of at least 5 amino acid residues, at least 10 aminoacid residues, at least 15 amino acid residues, at least 20 amino acidresidues, at least 25 amino acid residues, at least 40 amino acidresidues, at least 50 amino acid residues, at least 60 amino residues,at least 70 amino acid residues, at least 80 amino acid residues, atleast 90 amino acid residues, at least 100 amino acid residues, at least125 amino acid residues, or at least 150 amino acid residues; and (c) apolypeptide encoded by a nucleotide sequence that is at least 30%, atleast 35%, at least 40%, at least 45%, at least 50%, at least 55%, atleast 60%, at least 65%, at least 70%, at least 75%, at least 80%, atleast 85%, at least 90%, at least 95% or at least 99% identical to thenucleotide sequence encoding a RSV polypeptide, a fragment of a RSVpolypeptide, an antibody, or antibody fragment described herein. Apolypeptide with similar structure to a RSV polypeptide, a fragment of aRSV polypeptide, an antibody, or antibody fragment described hereinrefers to a polypeptide that has a similar secondary, tertiary orquaternary structure of a RSV polypeptide, a fragment of a RSV, anantibody, or antibody fragment described herein. The structure of apolypeptide can determined by methods known to those skilled in the art,including but not limited to, X-ray crystallography, nuclear magneticresonance, and crystallographic electron microscopy.

The term “derivative” as used herein refers to a polypeptide thatcomprises an amino acid sequence of a RSV polypeptide, a fragment of aRSV polypeptide, an antibody that immunospecifically binds to a RSVpolypeptide, or an antibody fragment that immunospecifically binds to aRSV polypeptide which has been altered by the introduction of amino acidresidue substitutions, deletions or additions. The term “derivative” asused herein also refers to a RSV polypeptide, a fragment of a RSVpolypeptide, an antibody that immunospecifically binds to a RSVpolypeptide, or an antibody fragment that immunospecifically binds to aRSV polypeptide which has been modified, i.e, by the covalent attachmentof any type of molecule to the polypeptide. For example, but not by wayof limitation, a RSV polypeptide, a fragment of a RSV polypeptide, anantibody, or antibody fragment may be modified, e.g., by glycosylation,acetylation, pegylation, phosphorylation, amidation, derivatization byknown protecting/blocking groups, proteolytic cleavage, linkage to acellular ligand or other protein, etc. A derivative of a RSVpolypeptide, a fragment of a RSV polypeptide, an antibody, or antibodyfragment may be modified by chemical modifications using techniquesknown to those of skill in the art, including, but not limited tospecific chemical cleavage, acetylation, formylation, metabolicsynthesis of tunicamycin, etc. Further, a derivative of a RSVpolypeptide, a fragment of a RSV polypeptide, an antibody, or antibodyfragment may contain one or more non-classical amino acids. Apolypeptide derivative possesses a similar or identical function as aRSV polypeptide, a fragment of a RSV polypeptide, an antibody, orantibody fragment described herein.

The term “effective neutralizing titer” as used herein refers to theamount of antibody which corresponds to the amount present in the serumof animals (human or cotton rat) that has been shown to be eitherclinically efficacious (in humans) or to reduce virus by 99% in, forexample, cotton rats. The 99% reduction is defined by a specificchallenge of, e.g., 10³ pfu, 10⁴ pfu, 10⁵ pfu, 106 pfu, 10⁷ pfu, 10⁸pfu, or 10⁹ pfu) of RSV.

The term “epitopes” as used herein refers to portions of a RSVpolypeptide having antigenic or immunogenic activity in an animal,preferably a mammal, and most preferably in a human. An epitope havingimmunogenic activity is a portion of a RSV polypeptide that elicits anantibody response in an animal. An eptiope having antigenic activity isa portion of a RSV polypeptide to which an antibody immunospecificallybinds as determined by any method well known in the art, for example, bythe immunoassays described herein. Antigenic epitopes need notnecessarily be immunogenic.

The term “fragment” as used herein refers to a peptide or polypeptidecomprising an amino acid sequence of at least 5 contiguous amino acidresidues, at least 10 contiguous amino acid residues, at least 15contiguous amino acid residues, at least 20 contiguous amino acidresidues, at least 25 contiguous amino acid residues, at least 40contiguous amino acid residues, at least 50 contiguous amino acidresidues, at least 60 contiguous amino residues, at least 70 contiguousamino acid residues, at least contiguous 80 amino acid residues, atleast contiguous 90 amino acid residues, at least contiguous 100 aminoacid residues, at least contiguous 125 amino acid residues, at least 150contiguous amino acid residues, at least contiguous 175 amino acidresidues, at least contiguous 200 amino acid residues, or at leastcontiguous 250 amino acid residues of the amino acid sequence of a RSVpolypeptide or an antibody that immunospecifically binds to a RSVpolypeptide.

The term “human infant” as used herein refers to a human less than 24months, preferably less than 16 months, less than 12 months, less than 6months, less than 3 months, less than 2 months, or less than 1 month ofage.

The term “human infant born prematurely” as used herein refers to ahuman born at less than 40 weeks gestational age, preferably less than35 weeks gestational age, who is less than 6 months old, preferably lessthan 3 months old, more preferably less than 2 months old, and mostpreferably less than 1 month old.

An “isolated” or “purified” antibody or fragment thereof issubstantially free of cellular material or other contaminating proteinsfrom the cell or tissue source from which the protein is derived, orsubstantially free of chemical precursors or other chemicals whenchemically synthesized. The language “substantially free of cellularmaterial” includes preparations of an antibody or antibody fragment inwhich the antibody or antibody fragment is separated from cellularcomponents of the cells from which it is isolated or recombinantlyproduced. Thus, an antibody or antibody fragment that is substantiallyfree of cellular material includes preparations of antibody or antibodyfragment having less than about 30%, 20%, 10%, or 5% (by dry weight) ofheterologous protein (also referred to herein as a “contaminatingprotein”). When the antibody or antibody fragment is recombinantlyproduced, it is also preferably substantially free of culture medium,i.e., culture medium represents less than about 20%, 10%, or 5% of thevolume of the protein preparation. When the antibody or antibodyfragment is produced by chemical synthesis, it is preferablysubstantially free of chemical precursors or other chemicals, i.e., itis separated from chemical precursors or other chemicals which areinvolved in the synthesis of the protein. Accordingly such preparationsof the antibody or antibody fragment have less than about 30%, 20%, 10%,5% (by dry weight) of chemical precursors or compounds other than theantibody or antibody fragment of interest. In a preferred embodiment,antibodies of the invention or fragments thereof are isolated orpurified.

An “isolated” nucleic acid molecule is one which is separated from othernucleic acid molecules which are present in the natural source of thenucleic acid molecule. Moreover, an “isolated” nucleic acid molecule,such as a cDNA molecule, can be substantially free of other cellularmaterial, or culture medium when produced by recombinant techniques, orsubstantially free of chemical precursors or other chemicals whenchemically synthesized. In a preferred embodiment, nucleic acidmolecules encoding antibodies of the invention or fragments thereof areisolated or purified.

The term “fusion protein” as used herein refers to a polypeptide thatcomprises an amino acid sequence of an antibody or fragment thereof andan amino acid sequence of a heterologous polypeptide (e.g., anon-anti-RSV antigen antibody).

The term “high potency” as used herein refers to antibodies or fragmentsthereof that exhibit high potency as determined in various assays forbiological activity (e.g., neutralization of RSV) such as thosedescribed herein. For example, high potency antibodies of the presentinvention or fragments thereof have an EC₅₀ value less than 0.01 nM,less than 0.025 nM, less than 0.05 nM, less than 0.1 nM, less than 0.25nM, less than 0.5 nM, less than 0.75 nM, less than 1 nM, less than 1.25nM, less than 1.5 nM, less than 1.75 nM, or less than 2 nM as measuredby a microneutralization assay described herein. Further, high potencyantibodies of the present invention or fragments thereof result in atleast a 75%, preferably at least a 95% and more preferably a 99% lowerRSV titer in a cotton rat 5 days after challenge with 10⁵ pfu relativeto a cotton rat not administered said antibodies or antibody fragments.In certain embodiments of the invention, high potency antibodies of thepresent invention or fragments thereof exhibit a high affinity and/orhigh avidity for one or more RSV antigens (e.g., antibodies or antibodyfragments having an affinity of at least 2×10⁸ M⁻¹, at least 2.5×10⁸M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹,at least 10¹² M⁻¹, or at least 5×10¹² M⁻¹ for one or more RSV antigens).

The term “host” as used herein refers to a mammal, preferably a human.

The term “host cell” as used herein refers to the particular subjectcell transfected with a nucleic acid molecule and the progeny orpotential progeny of such a cell. Progeny of such a cell may not beidentical to the parent cell transfected with the nucleic acid moleculedue to mutations or environmental influences that may occur insucceeding generations or integration of the nucleic acid molecule intothe host cell genome.

In certain embodiments of the invention, a “prophylactically effectiveserum titer” is the serum titer in a mammal, preferably a human, thatreduces the incidence of a RSV infection in said mammal. Preferably, theprophylactically effective serum titer reduces the incidence of RSVinfections in humans with the greatest probability of complicationsresulting from RSV infection (e.g., a human with cystic fibrosis,bronchopulmonary dysplasia, congenital heart disease, congenitalimmunodeficiency or acquired immunodeficiency, a human who has had abone marrow transplant, a human infant, or an elderly human). In certainother embodiments of the invention, a “prophylactically effective serumtiter” is the serum titer in a cotton rat that results in a RSV titer 5days after challenge with 10⁵ pfu that is 99% lower than the RSV titer 5days after challenge with 10⁵ pfu of RSV in a cotton rat notadministered an antibody or antibody fragment that immunospecificallybinds to a RSV antigen.

In certain embodiments of the invention, a “therapeutically effectiveserum titer” is the serum titer in a mammal, preferably a human, thatreduces the severity, the duration and/or the symptoms associated with aRSV infection in said mammal. Preferably, the therapeutically effectiveserum titer reduces the severity, the duration and/or the numbersymptoms associated with RSV infections in humans with the greatestprobability of complications resulting from a RSV infection (e.g., ahuman with cystic fibrosis, bronchopulmonary dysplasia, congenital heartdisease, congenital immunodeficiency or acquired immunodeficiency, ahuman who has had a bone marrow transplant, a human infant, or anelderly human). In certain other embodiments of the invention, a“therapeutically effective serum titer” is the serum titer in a cottonrat that results in a RSV titer 5 days after challenge with 10⁵ pfu thatis 99% lower than the RSV titer 5 days after challenge with 10⁵ pfu ofRSV in a cotton rat not administered an antibody or antibody fragmentthat immunospecifically binds to a RSV antigen.

As used herein, “HL-SYNAGIS” is SYNAGIS® with one or more modificationsin amino acid residues identified to be involved in the interactionbetween the Fc domain of SYNAGIS® and the FcRn receptor which results inan increase in the in vivo half-life of SYNAGIS® to greater than 21days. An antigen-binding fragment of HL-SYNAGIS is a fragment ofSYNAGIS® which immunospecifically binds to RSV F glycoprotein and hasone or more modifications in amino acid residues identified to beinvolved in the interaction between the Fc domain of SYNAGIS® and theFcRn receptor, wherein said modifications result in an increase in thein vivo half-life of the antigen-binding fragment. In accordance withthe invention, HL-SYNAGIS or an antigen-binding fragment thereof has anin vivo half-life of at least 25 days, preferably at least 30 days, morepreferably at least 35 days, and most preferably at least 40 days.

The term “RSV antigen” refers to a RSV polypeptide or fragment thereofto which an antibody or antibody fragment immunospecifically binds. AnRSV antigen also refers to an analog or derivative of a RSV polypeptideor fragment thereof to which an antibody or antibody fragmentimmunospecifically binds.

The term “serum titer” as used herein refers to an average serum titerin a population of least 10, preferably at least 20, and most preferablyat least 40 subjects.

The term “antibodies or fragments that immunospecifically bind to a RSVantigen” as used herein refers to antibodies or fragments thereof thatspecifically bind to a RSV polypeptide or a fragment of a RSVpolypeptide and do not non-specifically bind to other polypeptides.Antibodies or fragments that immunospecifically bind to a RSVpolypeptide or fragment thereof may have cross-reactivity with otherantigens. Preferably, antibodies or fragments that immunospecificallybind to a RSV polypeptide or fragment thereof do not cross-react withother antigens. Antibodies or fragments that immunospecifically bind toa RSV polypeptide can be identified, for example, by immunoassays orother techniques known to those of skill in the art.

To determine the percent identity of two amino acid sequences or of twonucleic acid sequences, the sequences are aligned for optimal comparisonpurposes (e.g., gaps can be introduced in the sequence of a first aminoacid or nucleic acid sequence for optimal alignment with a second aminoacid or nucleic acid sequence). The amino acid residues or nucleotidesat corresponding amino acid positions or nucleotide positions are thencompared. When a position in the first sequence is occupied by the sameamino acid residue or nucleotide as the corresponding position in thesecond sequence, then the molecules are identical at that position. Thepercent identity between the two sequences is a function of the numberof identical positions shared by the sequences (i.e., % identity=numberof identical overlapping positions/total number of positions×100%). Inone embodiment, the two sequences are the same length.

The determination of percent identity between two sequences can also beaccomplished using a mathematical algorithm. A preferred, non-limitingexample of a mathematical algorithm utilized for the comparison of twosequences is the algorithm of Karlin and Altschul, 1990, Proc. Natl.Acad. Sci. U.S.A. 87:2264-2268, modified as in Karlin and Altschul,1993, Proc. Natl. Acad. Sci. U.S.A. 90:5873-5877. Such an algorithm isincorporated into the NBLAST and XBLAST programs of Altschul et al.,1990, J. Mol. Biol. 215:403. BLAST nucleotide searches can be performedwith the NBLAST nucleotide program parameters set, e.g., for score=100,wordlength=12 to obtain nucleotide sequences homologous to a nucleicacid molecules of the present invention. BLAST protein searches can beperformed with the XBLAST program parameters set, e.g., to score-50,wordlength=3 to obtain amino acid sequences homologous to a proteinmolecule of the present invention. To obtain gapped alignments forcomparison purposes, Gapped BLAST can be utilized as described inAltschul et al., 1997, Nucleic Acids Res. 25:3389-3402. Alternatively,PSI-BLAST can be used to perform an iterated search which detectsdistant relationships between molecules (Id.). When utilizing BLAST,Gapped BLAST, and PSI-Blast programs, the default parameters of therespective programs (e.g., of XBLAST and NBLAST) can be used (see, e.g.,http://www.ncbi.nlm.nih.gov). Another preferred, non-limiting example ofa mathematical algorithm utilized for the comparison of sequences is thealgorithm of Myers and Miller, 1988, CABIOS 4:11-17. Such an algorithmis incorporated in the ALIGN program (version 2.0) which is part of theGCG sequence alignment software package. When utilizing the ALIGNprogram for comparing amino acid sequences, a PAM120 weight residuetable, a gap length penalty of 12, and a gap penalty of 4 can be used.

The percent identity between two sequences can be determined usingtechniques similar to those described above, with or without allowinggaps. In calculating percent identity, typically only exact matches arecounted.

4. DESCRIPTION OF THE FIGURES

FIGS. 1A-1B show the amino acid sequences of the (A) light chainvariable region (SEQ ID NO:260) and (B) heavy chain variable region (SEQID NO:261) of a high affinity monoclonal antibody that binds to a RSVantigen the potency of which can be increased by methods describedherein or in Applicants' copending applications Ser. Nos. 60/168,426 and60/186,252. For reference purposes, this is the amino acid sequence ofthe SYNAGIS® antibody disclosed in Johnson et al, 1997, J. Infect. Dis.176:1215-1224 and U.S. Pat. No. 5,824,307. Here, the CDR regions areunderlined while non-underlined residues form the framework regions ofthe variable regions of each antibody. In this antibody, the CDRs arederived from a mouse antibody while the framework regions are derivedfrom a human antibody. The constant regions (not shown) are also derivedfrom a human antibody.

FIGS. 2A-2B show the (A) light chain variable region (SEQ ID NO:262) and(B) heavy light chain variable region (SEQ ID NO:263) for an antibodysequence. CDR regions are underlined. This sequence differs from thesequence disclosed in FIGS. 1A-1B in the first 4 residues of VH CDR1 ofthe light chain, residue 103 of the light chain and residue 112 of theheavy chain.

5. DETAILED DESCRIPTION OF THE INVENTION

The present invention provides methods of preventing, neutralizing,treating and ameliorating one or more symptoms associated with a RSVinfection in a subject comprising administering to said subject one ormore antibodies which immunospecifically bind to one or more RSVantigens with high affinity and/or high avidity and/or have a longerserum half-life. The high affinity and/or high avidity of the antibodiesof the invention enable the use of lower doses of said antibodies thanpreviously thought to be effective for the prevention, neutralization,treatment and the amelioration of symptoms associated with RSVinfection. The use of lower doses of antibodies which immunospecificallybind to one or more RSV antigens reduces the likelihood of adverseeffects, as well as providing a more effective prophylaxis. Further, thehigh affinity and/or high avidity of the antibodies of the inventionenable less frequent administration of said antibodies than previouslythought to be necessary for the prevention, neutralization, treatmentand the amelioration of symptoms associated with RSV infection.

The present invention also provides methods of preventing, neutralizing,treating and ameliorating one or more symptoms associated with a RSVinfection in a subject comprising administering to said subject one ormore antibodies which immunospecifically bind to one or more RSVantigens, said antibodies having a longer half-life than otherpreviously known antibodies.

The present invention also provides improved methods of administeringone or more antibodies which immunospecifically bind to one or more RSVantigens to a subject, said methods enable lower doses of saidantibodies to be administered to the subject while achieving serumtiters effective for the prevention, neutralization, treatment andamelioration of one or more symptoms associated with RSV infection. Thepresent invention encompasses methods of delivering one or moreantibodies which immunospecifically bind to one or more RSV antigensdirectly to the site of RSV infection. In particular, the inventionencompasses pulmonary delivery of one or more antibodies whichimmunospecifically bind to one or more RSV antigens. The improvedmethods of delivering of one or more antibodies which immunospecificallybind to one or more RSV antigens reduces the dosage and frequency ofadministration of said antibodies to a subject.

The present invention is based, in part, upon achieving or inducing aserum titer of 1 μg/ml or less, preferably 2 μg/ml or less, 5 μg/ml orless, 6 μg/ml or less, 10 μg/ml or less, 15 μg/ml or less, 20 μg/ml orless, or 25 μg/ml or less of an antibody or fragment thereof thatimmunospecifically binds to a respiratory syncytial virus (RSV) antigenin a mammal with higher affinity and/or higher avidity than previouslyknown antibodies, while reducing or avoiding adverse affects. Preferablya serum titer or serum titer of 1 μg/ml or less, preferably 2 μg/ml orless, 5 μg/ml or less, 6 μg/ml or less, 10 μg/ml or less, 15 μg/ml orless, 20 μg/ml or less, or 25 μg/ml or less is achieved approximately 20days (preferably 25, 30, 35 or 40 days) after administration of a firstdose of antibodies or fragments thereof which immunospecifically bind toa RSV antigen and without administration of any other doses of saidantibodies or fragments thereof.

The present invention provides methods of achieving or inducing a serumtiter of at least 30 μg/ml, at least 40 μg/ml, at least 50 μg/ml, atleast 75 μg/ml, at least 100 μg/ml, at least 125 μg/ml, at least 150μg/ml, at least 175 μg/ml, at least 200 μg/ml, at least 225 μg/ml, atleast 250 μg/ml, at least 275 μg/ml, at least 300 μg/ml, at least 325μg/ml, at least 350 μg/ml, at least 375 μg/ml, or at least 400 μg/ml ofan antibody or fragment thereof that immunospecifically binds to arespiratory syncytial virus (RSV) antigen in a mammal, while reducing oravoiding adverse affects. Preferably a serum titer or serum titer of atleast 30 μg/ml, preferably at least 40 μg/ml, at least 50 μg/ml, atleast 75 μg/ml, at least 100 μg/ml, at least 125 μg/ml, at least 150μg/ml, at least 175 μg/ml, at least 200 μg/ml, at least 225 μg/ml, atleast 250 μg/ml, at least 275 μg/ml, at least 300 μg/ml, at least 325μg/ml, at least 350 μg/ml, at least 375 μg/ml, or at least 400 μg/ml isachieved approximately 30 days after administration of a first dose ofantibodies or fragments thereof which immunospecifically bind to a RSVantigen and without administration of any other doses of said antibodiesor fragments thereof.

In a specific embodiment, a serum titer in a non-primate mammal of atleast 40 μg/ml, preferably at least 80 μg/ml, at least 100 μg/ml, atleast 120 μg/ml, at least 150 μg/ml, at least 200 μg/ml, at least 250μg/ml, or at least 300 μg/ml, of one or more antibodies or fragmentsthereof that immunospecifically bind to one or more RSV antigens isachieved at least 1 day after administering a dose of less than 2.5mg/kg, preferably less than 1 mg/kg, or less than 0.5 mg/kg of theantibodies or antibody fragments to the non-primate mammal. In anotherembodiment, a serum titer in a non-primate mammal of at least 150 μg/ml,preferably at least 200 μg/ml, at least 250 μg/ml, at least 300 μg/ml,at least 350 μg/ml, or at least 400 μg/ml of one or more antibodies orfragments thereof that immunospecifically bind to one or more RSVantigens is achieved at least 1 day after administering a dose ofapproximately 5 mg/kg of the antibodies or antibody fragments to thenon-primate mammal.

In another embodiment, a serum titer in a primate of at least 40 μg/ml,preferably at least 80 μg/ml, at least 100 μg/ml, at least 120 μg/ml, atleast 150 μg/ml, at least 200 μg/ml, at least 250 μg/ml, or at least 300μg/ml of one or more antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens is achieved at least30 days after administering a first dose of less than 5 mg/kg,preferably less than 3 mg/kg, less than 1 mg/kg, or less than 0.5 mg/kgof the antibodies or fragments thereof to the primate. In yet anotherembodiment, a serum titer in a primate of at least 200 μg/ml, at least250 μg/ml, at least 300 μg/ml, at least 350 μg/ml, or at least 400 μg/mlof one or more antibodies or fragments thereof that immunospecificallybind to one or more RSV antigens is achieved at least 30 days afteradministering a first dose of approximately 15 mg/kg of the antibodiesor fragments thereof to the primate. In accordance with theseembodiments, the primate is preferably a human.

The present invention provides methods for preventing, treating, orameliorating one or more symptoms associated with a RSV infection in amammal, preferably a human, said methods comprising administering afirst dose to said mammal of a prophylactically or therapeuticallyeffective amount of one or more antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens, wherein saideffective amount is less than 15 mg/kg of said antibodies or fragmentsthereof and which results in a serum titer of greater than 40 μg/ml 30days after the first administration and prior to any subsequentadministration. In one embodiment, RSV infection in a human subject isprevented or treated, or one or more symptoms associated with RSVinfection is ameliorated by administering a first dose of less than 10mg/kg, preferably less than 5 mg/kg, less than 3 mg/kg, or less than 1mg/kg of one or more antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens so that a serumantibody titer of at least 40 μg/ml, preferably at least 80 μg/ml, or atleast 120 μg/ml, at least 150 μg/ml, at least 200 μg/ml, at least 250μg/ml, or at least 300 μg/ml is achieved 30 days after theadministration of the first dose of the antibodies or antibody fragmentsand prior to the administration of a subsequent dose. In anotherembodiment, RSV infection in a human subject is prevented or treated, orone or more symptoms associated with a RSV infection is ameliorated byadministering a first dose of approximately 15 mg/kg of one or moreantibodies or fragments thereof that immunospecifically bind to one ormore RSV antigens so that a serum antibody titer of at least 75 μg/ml,preferably at least 100 μg/ml, at least 200 μg/ml, at least 250 μg/ml,at least 300 μg/ml, at least 350 μg/ml, or at least 400 μg/ml isachieved 30 days after the administration of the first dose of theantibodies or antibody fragments and prior to the administration of asubsequent dose. In yet another embodiment, RSV infection in a humansubject is prevented or treated, or one or more symptoms associated witha RSV infection is ameliorated by administering a first dose of one ormore antibodies or fragments thereof that immunospecifically bind to oneor more RSV antigens such that a prophylactically or therapeuticallyeffective serum titer of less than 10 μg/ml, preferably less than 5μg/ml, less than 3 μg/ml, less than 1 μg/ml, or less than 0.5 μg/ml isachieved no more than 30 days after administering the antibodies orantibody fragments. In accordance with this embodiment, the first doseof one or more antibodies or fragments thereof is less than 10 mg/kg,preferably less than 5 mg/kg, less than 1 mg/kg, or less than 0.5 mg/kg.

The present invention provides antibodies or fragments thereof whichimmunospecifically bind to a RSV antigen with an affinity constant of atleast 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, atleast 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹, at least 5×10¹²M⁻¹, at least 10¹³ M⁻¹, at least 5×10¹³ M⁻¹, at least 10¹⁴ M⁻¹, at least5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹, or at least 5×10¹⁵ M⁻¹. Preferably, theantibodies or antibody fragments have a higher affinity for a RSVantigen than SYNAGIS® does for the RSV F glycoprotein. The presentinvention also provides pharmaceutical compositions comprising one ormore antibodies which immunospecifically bind to a RSV antigen with anaffinity constant of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, atleast 5×10¹¹ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹²M⁻¹, at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹, at least 5×10¹³ M⁻¹, atleast 10¹⁴ M⁻¹, at least 5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹, or at least5×10¹⁵ M⁻¹.

The present invention also provides antibodies or fragments thereofwhich immunospecifically bind to a RSV antigen with a higher aviditythan any previously known antibodies or fragments thereof. Preferably,the antibodies or antibody fragments have higher avidity for a RSVantigen than SYNAGIS® has for the RSV F glycoprotein. The presentinvention also provides antibodies or fragments thereof thatimmunospecifically bind to a RSV antigen which have a higher affinityfor a RSV antigen than any previously known antibodies or fragmentsthereof. The present invention also provides pharmaceutical compositionscomprising one or more antibodies or fragments thereof whichimmunospecifically bind to a RSV antigen with a higher avidity than anypreviously known antibodies or fragments thereof.

The present invention also provides for antibodies or fragments thereofwhich immunospecifically bind to one or more RSV antigens with anaffinity constant of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, atleast 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹²M⁻¹, at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹, at least 5×10¹³ M⁻¹, atleast 10¹⁴ M⁻¹, at least 5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹, or at least5×10¹⁵ M⁻¹ and which have a higher avidity for one or more RSV antigensthan any previously known antibodies or fragments thereof such as, e.g.,SYNAGIS®. The present invention further provides pharmaceuticalcompositions comprising one or more antibodies or fragments thereofwhich immunospecifically bind to one or more RSV antigens with anaffinity constant of at least 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, atleast 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹²M⁻¹, at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹, at least 5×10¹³ M⁻¹, atleast 10¹⁴ M⁻¹, at least 5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹, or at least5×10¹⁵ M⁻¹ and which have a higher avidity for one or more RSV antigensthan any previously known antibodies or fragments thereof such as, e.g.,SYNAGIS®.

The present invention provides methods of achieving a certain serumtiter (preferably a serum titer 1 μg/ml or less, 2 μg/ml or less, 5μg/ml or less, 6 μg/ml or less, 10 μg/ml or less, 15 μg/ml or less, 20μg/ml or less, or 25 μg/ml or less) of antibodies or fragments thereofthat immunospecifically bind to one or more RSV antigens in a mammal,said methods comprising administering to said mammal one or moreantibodies or fragments thereof that have an affinity constant of atleast 2×10⁸ M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, atleast 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹, at least 5×10¹²M⁻¹, at least 10¹³ M⁻¹, at least 5×10¹³ M⁻¹, at least 10¹⁴ M⁻¹, at least5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹, or at least 5×10¹⁵ M⁻¹ for said RSVantigens. Preferably, the antibodies or antibody fragments have a higheraffinity for a RSV antigen than SYNAGIS® does for the RSV Fglycoprotein.

The present invention also provides methods of achieving a certain serumtiter of antibodies or fragments thereof that immunospecifically bind toone or more RSV antigens in a mammal, said methods comprisingadministering to said mammal one or more antibodies or fragments thereofthat have a higher avidity for said RSV antigens than any previouslyknown antibodies or antibody fragments. Preferably, the antibodies orantibody fragments have higher avidity for a RSV antigen than SYNAGIS®has for the RSV F glycoprotein.

The present invention also provides methods of achieving a certain serumtiter of antibodies or fragments thereof that immunospecifically bind toone or more RSV antigens in mammal, said methods comprisingadministering to said mammal one or more antibodies or fragments thereofthat have an affinity constant of at least 2×10⁸ M⁻¹, at least 2.5×10⁸M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹,at least 10¹² M⁻¹, at least 5×10¹² M⁻¹, at least 10¹³M⁻¹, at least5×10¹³ M⁻¹, at least 10¹⁴ M⁻¹, at least 5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹,or at least 5×10¹⁵ M⁻¹ for one or more RSV antigens and have a higheravidity than any previously known antibodies or antibody fragments forsaid RSV antigens.

The present invention also provides methods of neutralizing RSV usingantibodies or fragments thereof that immunospecifically bind to one ormore RSV antigens and which have an affinity constant of at least 2×10⁸M⁻¹, at least 2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, atleast 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹, at least 5×10¹² M⁻¹, atleast 101³M⁻¹, at least 5×10 3 M⁻¹, at least 10¹⁴ M⁻¹, at least 5×10¹⁴M⁻¹, at least 10¹⁵ M⁻¹, or at least 5×10¹⁵ M⁻¹ for said RSV antigens.Preferably, the antibodies or antibody fragments have a higher affinityfor a RSV antigen than SYNAGIS® does for the RSV F glycoprotein. Thepresent invention also provides methods of neutralizing RSV usingantibodies or fragments thereof that immunospecifically bind to one ormore RSV antigens and which have a higher avidity for said RSV antigensthan any previously known antibodies or antibody fragments. Preferably,the antibodies or antibody fragments have a higher avidity for a RSVantigen than SYNAGIS® does for the RSV F glycoprotein. The presentinvention also provides methods of neutralizing RSV using antibodies orfragments thereof that immunospecifically bind to one or more RSVantigens with an affinity constant of at least 2×10⁸ M⁻¹, at least2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹,at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least5×10¹¹ M⁻¹, at least 10¹² M⁻¹, at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹,at least 5×10¹³ M⁻¹ at least 10¹⁴ M⁻¹, at least 5×10¹⁴ M⁻¹, at least10¹⁵ M⁻¹, or at least 5×10¹⁵ M⁻¹ and which have a higher avidity forsaid RSV antigens than any previously known antibodies or antibodyfragments. The higher affinity and/or higher avidity that theseantibodies or antibody fragments have for a RSV antigen results in alower concentration of these antibodies or antibody fragments necessaryto achieve neutralization of RSV than previously known.

The present invention also provides methods for preventing, treating orameliorating one or more symptoms of RSV infection in a mammal, saidmethods comprising administering to said mammal one or more antibodiesor fragments thereof that immunospecifically bind to one or more RSVantigens and which have an affinity constant of at least 2×10⁸ M⁻¹, atleast 2.5×10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least5×10¹¹ M⁻¹, at least 10¹² M⁻¹, at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹,at least 5×10¹³ M⁻¹, at least 10¹⁴ M⁻¹, at least 5×10¹⁴′ M⁻¹, at least10¹⁵ M⁻¹, or at least 5×10¹⁵ M⁻¹ for said RSV antigens. Preferably, theantibodies or antibody fragments have a higher affinity for a RSVantigen than SYNAGIS® does for the RSV F glycoprotein. The presentinvention also provides of methods preventing, treating or amelioratingone or more symptoms of RSV infection in a mammal, said methodscomprising administering to said mammal one or more antibodies orfragments thereof that immunospecifically bind to one or more RSVantigen and which have a higher avidity for said RSV antigen than anypreviously known antibodies or antibody fragments. Preferably, theantibodies or antibody fragments have a higher avidity for a RSV antigenthan SYNAGIS® does for the RSV F glycoprotein. The present inventionfurther provides methods of preventing, treating or ameliorating one ormore symptoms of RSV infection in a mammal, said methods comprisingadministering to said mammal one or more antibodies or fragments thereofthat immunospecifically bind to one or more RSV antigens with anaffinity constant of at least 2×10⁸ M⁻¹, at least 2.5×10 M⁻¹, at least5×10⁸ M⁻¹, at least 10⁹ M⁻¹, at least 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, atleast 5×10¹⁰ M⁻¹, at least 10¹¹ M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹²M⁻¹, at least 5×10¹² M⁻¹, at least 10¹³ M⁻¹, at least 5×10¹³ M⁻¹, atleast 10¹⁴ M⁻¹, at least 5×10¹⁴ M⁻¹, at least 10¹⁵ M⁻¹, or at least5×10¹⁵ M⁻¹ for said RSV antigen and which have a higher avidity for saidRSV antigens than any previously known antibodies or antibody fragments.The higher affinity and/or higher avidity that these antibodies orantibody fragments have for a RSV antigen results in lower and/or lessfrequent doses of these antibodies or antibody fragments to achieve aprophylactic or therapeutic effect in a mammal, preferably a human, thanpreviously known.

The present invention provides methods for preventing, treating, orameliorating one or more symptoms associated with a RSV infection in amammal, preferably a human, said methods comprising administering afirst dose to said mammal of a prophylactically or therapeuticallyeffective amount of one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens with a higheravidity and/or affinity than previously known antibodies such asSYNAGIS®, wherein said effective amount is less than 15 mg/kg of saidantibodies or fragments thereof and which results in a serum titer lessthan 30 μg/ml (which is preferably at least 2 μg/ml, more preferably atleast 4 μg/ml, and most preferably at least 6 μg/ml) 30 days after thefirst administration and prior to any subsequent administration. In oneembodiment, RSV infection in a human subject is prevented or treated, orone or more symptoms in a human subject is ameliorated by administeringa first dose of less than 10 mg/kg, preferably less than 5 mg/kg, lessthan 3 mg/kg, less than 1 mg/kg, or less than 0.5 mg/kg of one or moreantibodies or fragments thereof that immunospecifically bind to one ormore RSV antigens with a higher avidity and/or affinity than previouslyknown antibodies such as SYNAGIS® so that a serum antibody titer of atleast 6 μg/ml, preferably at least 10 μg/ml, at least 25 μg/ml, at least30 μg/ml, at least 40 μg/ml at least 80 μg/ml, or at least 120 μg/ml, atleast 150 μg/ml, at least 200 μg/ml, at least 250 μg/ml, or at least 300μg/ml is achieved 30 days after the administration of the first dose ofthe antibodies or antibody fragments and prior to the administration ofa subsequent dose.

The present invention provides antibodies or fragments thereofcomprising a variable heavy (“VH”) domain having an amino acid sequenceof any VH domain listed in Table 2, and pharmaceutical compositionscomprising said antibodies or antibody fragments. The present inventionalso provides antibodies or fragments thereof comprising one or more VHCDRs having the amino acid sequence of one or more VH CDRs listed inTable 2 and/or Table 3, and pharmaceutical compositions comprising saidantibodies or antibody fragments. The present invention also providesantibodies or fragments thereof comprising a variable light (“VL”)domain having the amino acid sequence of any VL domain listed in Table2, and pharmaceutical compositions comprising said antibodies orantibody fragments. The present invention also provides antibodies orfragments thereof comprising one or more VL CDRs having the amino acidsequence of one or more VL CDRs listed in Table 2 and/or Table 3, andpharmaceutical compositions comprising said antibodies or antibodyfragments. The present invention also provides antibodies or fragmentsthereof comprising a VH domain having the amino acid sequence any VHdomain listed in Table 2 and a VL domain having the amino acid sequenceof any VL domain listed in Table 2, and pharmaceutical compositionscomprising said antibodies or antibody fragments. The present inventionprovides antibodies or fragments thereof comprising one or more VH CDRshaving the amino acid sequence one or more VH CDRs listed in Table 2and/or Table 3 and one or more VL CDRs having the amino acid sequence ofone or more VL CDRs listed in Table 2 and/or Table 3. The presentinvention encompasses pharmaceutical compositions comprising saidantibodies or antibody fragments. Preferably, said antibodies orantibody fragments immunospecifically bind to one or more RSV antigens.

The present invention encompasses methods for preventing, treating,neutralizing and ameliorating one or more symptoms using one or moreantibodies comprising a variable heavy (“VH”) domain having an aminoacid sequence of any VH domain listed in Table 2. The present inventionalso encompasses methods for preventing, treating, neutralizing andameliorating one or more symptoms using one or more antibodiescomprising one or more VH CDRs having the amino acid sequence of one ormore VH CDRs listed in Table 2 and/or Table 3. The present inventionalso encompasses methods for preventing, treating, neutralizing andameliorating one or more symptoms using one or more antibodiescomprising a variable light (“VL”) domain having the amino acid sequenceof any VL domain listed in Table 2. The present invention alsoencompasses methods for preventing, treating, neutralizing andameliorating one or more symptoms using one or more antibodiescomprising one or more VL CDRs having the amino acid sequence of one ormore VL CDRs listed in Table 2 and/or Table 3. The present inventionalso encompasses methods for preventing, treating, neutralizing andameliorating one or more symptoms using one or more antibodiescomprising a VH domain having the amino acid sequence any VH domainlisted in Table 2 and a VL domain having the amino acid sequence of anyVL domain listed in Table 2. The present invention further encompassesmethods for preventing, treating, neutralizing and ameliorating one ormore symptoms using one or more antibodies comprising one or more VHCDRs having the amino acid sequence one or more VH CDRs listed in Table2 and/or Table 3 and one or more VL CDRs having the amino acid sequenceof one or more VL CDRs listed in Table 2 and/or Table 3. Preferably,said antibodies or antibody fragments immunospecifically bind to one ormore RSV antigens.

The present invention encompasses antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens with increased invivo half-lives. In particular, the present invention encompassesHL-SYNAGIS and antigen-binding fragments thereof. The present inventionalso encompasses novel antibodies or fragments thereof described hereinwhich immunospecifically bind to one or more RSV antigens and have an Fcdomain with a higher affinity for the FcRn receptor than the Fc domainof SYNAGIS®.

The present invention also encompasses methods for the prevention,neutralization, treatment or amelioration of one or more symptomsassociated with a RSV infection using antibodies or fragments thereofthat immunospecifically bind to one or more RSV antigens with increasedin vivo half-lives. In particular, the invention encompasses methods forthe prevention, neutralization, treatment or amelioration of one or moresymptoms associated with a RSV infection using HL-SYNAGIS or anantigen-binding fragment thereof. The invention also encompasses methodsfor the prevention, neutralization, treatment or amelioration of one ormore symptoms associated with a RSV infection using novel antibodies orfragments thereof described herein which immunospecifically bind to oneor more RSV antigens and have an Fc domain with a higher affinity forthe FcRn receptor than the Fc domain of SYNAGIS®.

The present invention provides sustained release formulations ofantibodies or fragments thereof that immunospecifically bind to one ormore RSV antigens for the prevention, neutralization, treatment oramelioration of one or more symptoms associated with a RSV infection. Inparticular, the present invention provides sustained releaseformulations of SYNAGIS® or fragments thereof for the prevention,neutralization, treatment or amelioration of one or more symptomsassociated with a RSV infection. The present invention also providessustained release formulations of one or more novel antibodies orfragments thereof described herein which immunospecifically bind to oneor more RSV antigens for the prevention, neutralization, treatment oramelioration of one or more symptoms associated with a RSV infection.

The present invention also provides methods of administeringcompositions comprising antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens to the site of a RSVinfection in a subject. In particular, the present invention providescompositions comprising one or more antibodies or fragments thereof forpulmonary delivery to a subject.

The present invention provides compositions comprising one or moreantibodies or fragments thereof that immunospecifically bind to one ormore RSV antigens, and methods for detecting or diagnosing a RSVinfection utilizing said antibodies or antibody fragments.

5.1. Antibodies

It should be recognized that antibodies that immunospecifically bind toa RSV antigen are known in the art. For example, SYNAGIS® is a humanizedmonoclonal antibody presently used for the prevention of RSV infectionin pediatric patients. The present invention encompasses novelformulations for administration of SYNAGIS® and other known anti-RSVantibodies and novel doses of SYNAGIS® and other known anti-RSVantibodies, as discussed herein.

In addition, the invention encompasses novel antibodies, fragments andother biological or macromolecules which immunospecifically bind to oneor more RSV antigens. With respect to these novel agents, the inventionfurther encompasses novel modes of administration, doses, dosing anduses based, in part, upon their unique therapeutic profiles and potency.

Set forth below, is a more detailed description of the antibodiesencompassed within the various aspects of the invention.

The present invention provides antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens. The presentinvention provides antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens. Preferably, theantibodies of the invention or fragments thereof immunospecifically bindto one or more RSV antigens regardless of the strain of RSV. The presentinvention also provides antibodies or fragments thereof thatdifferentially or preferentially bind to RSV antigens from one strain ofRSV versus another RSV strain. In a specific embodiment, the antibodiesof the invention or fragments thereof immunospecifically bind to the RSVF glycoprotein, G glycoprotein or SH protein. In a preferred embodiment,the antibodies present invention or fragments thereof immunospecificallybind to the RSV F glycoprotein. In another preferred embodiment, theantibodies of the present invention or fragments thereof bind to the A,B, or C antigenic sites of the RSV F glycoprotein.

Antibodies of the invention include, but are not limited to, monoclonalantibodies, multispecific antibodies, human antibodies, humanizedantibodies, chimeric antibodies, single-chain Fvs (scFv), single chainantibodies, Fab fragments, F(ab′) fragments, disulfide-linked Fvs(sdFv), and anti-idiotypic (anti-Id) antibodies (including, e.g.,anti-Id antibodies to antibodies of the invention), and epitope-bindingfragments of any of the above. In particular, antibodies of the presentinvention include immunoglobulin molecules and immunologically activeportions of immunoglobulin molecules, i.e., molecules that contain anantigen binding site that immunospecifically binds to a RSV antigen. Theimmunoglobulin molecules of the invention can be of any type (e.g., IgG,IgE, IgM, IgD, IgA and IgY), class (e.g., IgG₁, IgG₂, IgG₃, IgG₄, IgA₁,and IgA₂) or subclass of immunoglobulin molecule.

The antibodies of the invention may be from any animal origin includingbirds and mammals (e.g., human, murine, donkey, sheep, rabbit, goat,guinea pig, camel, horse, or chicken). Preferably, the antibodies of theinvention are human or humanized monoclonal antibodies. As used herein,“human” antibodies include antibodies having the amino acid sequence ofa human immunoglobulin and include antibodies isolated from humanimmunoglobulin libraries or from mice that express antibodies from humangenes.

The antibodies of the present invention may be monospecific, bispecific,trispecific or of greater multispecificity. Multispecific antibodies maybe specific for different epitopes of a RSV polypeptide or may bespecific for both a RSV polypeptide as well as for a heterologousepitope, such as a heterologous polypeptide or solid support material.See, e.g., PCT publications WO 93/17715, WO 92/08802, WO 91/00360, andWO 92/05793; Tutt, et al., J. Immunol. 147:60-69(1991); U.S. Pat. Nos.4,474,893, 4,714,681, 4,925,648, 5,573,920, and 5,601,819; and Kostelnyet al., J. Immunol. 148:1547-1553 (1992).

The present invention provides for antibodies or fragments thereof thatexhibit a high potency in an assay described herein. High potencyantibodies or fragments thereof can be produced by methods disclosed incopending U.S. patent application Ser. Nos. 60/168,426 and 60/186,252and methods described herein. For example, high potency antibodies canbe produced by genetically engineering appropriate antibody genesequences and expressing the antibody sequences in a suitable host. Theantibodies produced can be screened to identify antibodies with, e.g.,high k_(on) values in a BIAcore assay.

The present invention provides for antibodies or fragments thereof thathave a high binding affinity for one or more RSV antigens. In a specificembodiment, an antibody of the present invention or fragment thereof hasan association rate constant or k_(on) rate

$\left( {{{{antibody}\mspace{14mu}({Ab})} + {{antigen}\mspace{14mu}({Ag})}}\overset{k_{on}}{\rightarrow}{{Ab} - {Ag}}} \right)$of at least 10⁵M⁻¹s⁻¹, at least 5×10⁵M⁻¹s⁻¹, at least 10⁶ M⁻¹s⁻¹, atleast 5×10⁶ M⁻¹s⁻¹, at least 10⁷ M⁻¹s⁻¹, at least 5×10⁷ M⁻¹s⁻¹, or atleast 10⁸ M⁻¹s⁻¹. In a preferred embodiment, an antibody of the presentinvention or fragment thereof has a k_(on) of at least 2×10⁵ M⁻¹s⁻¹, atleast 5×10⁵ M⁻¹s⁻¹, at least 10⁶ M⁻¹s⁻¹, at least 5×10⁶ M⁻¹s⁻¹, at least10⁷M⁻¹s⁻, at least 5×10⁷M⁻¹s⁻¹, or at least 10⁸M⁻¹s⁻¹.

In another embodiment, an antibody of the present invention or fragmentthereof has a k_(off) rate

$\left( {{{{antibody}\mspace{14mu}({Ab})} + {{antigen}\mspace{14mu}({Ag})}}\overset{K_{off}}{\leftarrow}{{Ab} - {Ag}}} \right)$of less than 10^(−1 s) ⁻¹, less than 5×10⁻¹ s⁻¹, less than 10⁻² s⁻¹,less than 5×10⁻² s⁻¹, less than 10⁻³ s⁻¹, less than 5×10⁻³ s⁻¹, lessthan 10⁻⁴ s⁻¹, less than 5×10⁻⁴ s⁻¹, less than 10⁻⁵ s⁻¹, less than5×10⁻⁵ s⁻¹, less than 10⁻⁶ s⁻¹, less than 5×10⁻⁶ s⁻¹, less than 10⁻⁷s⁻¹, less than 5×10⁻⁷ s⁻¹, less than 10⁻⁸ s⁻¹, less than 5×10⁸ s⁻¹, lessthan 10⁻⁹ s⁻¹, less than 5×10⁻⁹ s⁻¹, or less than 10⁻¹⁰ s⁻¹. In apreferred embodiment, an antibody of the present invention or fragmentthereof has a k_(on) of less than 5×10⁻⁴ s⁻¹, less than 10⁻⁵ s⁻¹, lessthan 5×10⁻⁵s⁻¹, less than 10⁻⁶ s⁻¹, less than 5×10⁻⁶ s⁻¹, less than 10⁻⁷s⁻¹, less than 5×10⁻⁷ s⁻¹, less than 10⁻⁸ s⁻, less than 5×10⁻⁸ s⁻, lessthan 10⁻⁹ s⁻¹, less than 5×10⁻⁹ s⁻, or less than 10⁻¹⁰ s⁻¹.

In another embodiment, an antibody of the present invention or fragmentthereof has an affinity constant or K_(a) (k_(on)/k_(off)) of at least10² M⁻¹, at least 5×10² M⁻¹, at least 10³ M⁻¹, at least 5×10³ M⁻¹, atleast 10⁴ M⁻¹, at least 5×10⁴ M⁻¹, at least 10⁵ M⁻¹, at least 5×10⁵ M⁻¹,at least 10⁶ M⁻¹, at least 5×10⁶ M⁻¹, at least 10⁷ M⁻¹, at least5×10⁷M⁻¹, at least 10⁸ M⁻¹, at least 5×10⁸ M⁻¹, at least 10⁹ M⁻¹, atleast 5×10⁹ M⁻¹, at least 10¹⁰ M⁻¹, at least 5×10¹⁰ M⁻¹, at least 10¹¹M⁻¹, at least 5×10¹¹ M⁻¹, at least 10¹² M⁻¹, at least 5×10¹² M⁻¹, atleast 10¹³ M⁻¹, at least 5×10¹³ M⁻¹, at least 10¹⁴ M⁻¹, at least 5×10¹⁴M⁻¹, at least 10¹⁵ M⁻¹, or at least 5×10¹⁵ M⁻¹. In yet anotherembodiment, an antibody or fragment thereof has a dissociation constantor K_(d) (k_(off)/k_(on)) of less than 10⁻² M, less than 5×10⁻² M, lessthan 10⁻³ M, less than 5×10⁻³ M, less than 10⁻⁴ M, less than 5×10⁻⁴ M,less than 10⁻⁵ M, less than 5×10⁻⁵ M, less than 10⁻⁶ M, less than 5×10⁻⁶M, less than 10⁻⁷ M, less than 5×10⁻⁷ M, less than 10⁻⁸ M, less than5×10⁻⁸ M, less than 10⁻⁹ M, less than 5×10⁻⁹ M, less than 10⁻¹⁰ M, lessthan 5×10⁻¹¹ M, less than 10⁻¹¹ M, less than 5×10⁻¹¹ M, less than 10⁻¹²M, less than 5×10⁻¹² M, less than 10⁻¹³ M, less than 5×10⁻¹³ M, lessthan 10¹⁴ M, less than 5×10⁻¹⁴ M, less than 10⁻¹⁵ M, or less than5×10⁻¹⁵ M.

The present invention provides antibodies or fragment thereof that havea median effective concentration (EC₅₀) of less than 0.01 nM, less than0.025 nM, less than 0.05 nM, less than 0.1 nM, less than 0.25 nM, lessthan 0.5 nM, less than 0.75 nM, less than 1 nM, less than 1.25 nM, lessthan 1.5 nM, less than 1.75 nM, or less than 2 nM, in an in vitromicroneutralization assay The median effective concentration is theconcentration of antibody or antibody fragments that neutralizes 50% ofthe RSV in an in vitro microneutralization assay. In a preferredembodiment, antibody of the invention or fragment thereof has an EC₅₀ ofless than 0.01 nM, less than 0.025 nM, less than 0.05 nM, less than 0.1nM, less than 0.25 nM, less than 0.5 nM, less than 0.75 nM, less than 1nM, less than 1.25 nM, less than 1.5 nM, less than 1.75 nM, or less than2 nM, in an in vitro microneutralization assay.

In a specific embodiment, an antibody of the present invention isSYNAGIS® or an antibody-binding fragment thereof (e.g., one or morecomplementarity determining regions (CDRs) of SYNAGIS®). The amino acidsequence of SYNAGIS® is disclosed, e.g., in Johnson et al., 1997, J.Infectious Disease 176:1215-1224, and U.S. Pat. No. 5,824,307, each ofwhich is incorporated herein by reference in its entirety. Inalternative embodiment, an antibody of the present invention or fragmentthereof is not SYNAGIS® or a fragment of SYNAGIS®, i.e., is not anantibody comprising a VH domain of SEQ ID NO:7 and/or a VL domain of SEQID NO:8.

The present invention provides for antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens, said antibodies orantibody fragments comprising the amino acid sequence of SYNAGIS® withone or more amino acid residue substitutions in the variable light (VL)domain and/or variable heavy (VH) domain depicted in FIG. 1. The presentinvention also provides for antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens, said antibodies orantibody fragments comprising the amino acid sequence of SYNAGIS® withone or more amino acid residue substitutions in one or more VL CDRsand/or one or more VH CDRs. In a specific embodiment, an antibody orfragment thereof comprises the amino acid sequence of SYNAGIS® with oneor more amino acid residue substitutions of the amino acid residuesindicated in bold face and underlining in Table 1. In accordance withthis embodiment, the amino acid residue substitutions can beconservative or non-conservative. The antibody or antibody fragmentgenerated by introducing substitutions in the VH domain, VH CDRs, VLdomain and/or VL CDRs of SYNAGIS® can be tested in vitro and in vivo,for example, for its ability to bind to RSV F antigen, for its abilityto neutralize RSV, or for its ability to prevent, treat or ameliorateone or more symptoms associated with a RSV infection.

TABLE 1 CDR Sequences Of SYNAGIS ® CDR Sequence SEQ ID NO: VH1 T S GMSVG1 VH2 DIWWD D K KD YNPSLK S 2 VH3 S MI T N W YFDV 3 VL1 KCOLS VGYMH 4VL2 DT SKLA S 5 VL3 FQGS G YP F T 6 Bold faced & underlined amino acidresidues are preferred residues which should be substituted.

In a specific embodiment, an antibody of the present invention isSYNAGIS®, AFFF, Pf12, P12f4, P11d4, A1e9, A12a6, A13c4, A17d4, A4B4,A8c7, 1X-493L1FR, H3-3F4, M3H9, Y10H6, DG, AFFF(1), 6H8, L1-7E5,L2-15B10, A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, or A4B4-F52S.Preferably, an antibody of the present invention is AFFF, Pf12, P12f4,P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8c7, 1X-493L1FR, H3-3F4, M3H9,Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1),A4B4L1FR-S28R, or A4B4-F52S. In another embodiment, an antibody is a Fabfragment of SYNAGIS®, AFFF, Pf12, P12f4, P11d4, A1e9, A12a6, A13c4,A17d4, A4B4, A8c7, A4B4(1), A4B4L1FR-S28R, or A4B4-F52S.

AFFF, P12f2, P12f4, P11d4, Ale9, A12a6, A13c4, A17d4, A8C7, IX-493L1FR,H3-3F4, M3H9, Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, andA1h5 comprise the framework region and constant regions of SYNAGIS®.A4B4, A4B4(1), A4B4L1FR-S28R, and A4B4-F52S comprise the frameworkregion and constant regions of SYNAGIS® with the exception that there isvaline at position 103, numbered as shown in FIG. 2A, and a glutamine atposition 112, numbered as shown in FIG. 2B. In certain embodiments,A4B4, A4B4(1), A4B4L1FR-S28R, and A4B4-F52S comprise the frameworkregion and constant regions of SYNAGIS®.

In another embodiment, the present invention provides for anantigen-binding fragment of AFFF, Pf12, P12f4, P11d4, A1e9, A12a6,A13c4, A17d4, A4B4, A8c7, 1X-493L1FR, H3-3F4, M3H9, Y10H6, DG, AFFF(1),6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, orA4B4-F52S. In another embodiment, the present invention provides for oneor more antibodies or fragments thereof that immunospecifically bind toone or more RSV antigens, said antibodies or antibody fragmentscomprising a VH chain and/or VL chain having the amino acid sequence ofa VH chain and/or VL chain of AFFF, Pf12, P12f4, P11d4, A1e9, A12a6,A13c4, A17d4, A4B4, A8c7, 1X-493L1FR, H3-3F4, M3H9, Y10H6, DG, AFFF(1),6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, orA4B4-F52S. In another embodiment, the present invention provides for oneor more antibodies or fragments thereof that immunospecifically bind toone or more RSV antigens, said antibodies or antibody fragmentscomprising a VH domain and/or VL domain having the amino acid sequenceof a VH domain and/or VL domain of AFFF, Pf12, P12f4, P11d4, A1e9,A12a6, A13c4, A17d4, A4B4, A8c7, 1X-493L1FR, H3-3F4, M3H9, Y10H6, DG,AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, orA4B4-F52S. In another embodiment, the present invention provides forantibodies or fragments thereof that immunospecifically bind to one ormore RSV antigens, said antibodies or antibody fragments comprising oneor more CDRs having the amino acid sequence of one or more CDRs of AFFF,Pf12, P12f4, P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8c7, 1X-493L1FR,H3-3F4, M3H9, Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5,A4B4(1), A4B4L1FR-S28R, or A4B4-F52S. In yet another embodiment, thepresent invention provides for one or more antibodies or fragmentsthereof that immunospecifically bind to one or more RSV antigens, saidantibodies or antibody fragments comprising a combination of VH CDRsand/or VL CDRs having the amino acid sequence of VH CDRs and/or VL CDRsof AFFF, Pf12, P12f4, P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8c7,1X-493L1FR, H3-3F4, M3H9, Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10,A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, and/or A4B4-F52S.

The present invention provides antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens, said antibodies orantibody fragments comprising a variable heavy (“VH”) chain having anamino acid sequence of any one of the VL domains listed in Table 2. Thepresent invention also provides antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens, said antibodies orantibody fragments comprising a VH domain having an amino acid sequenceof any one of the VH domains listed in Table 2. In certain embodimentsof the invention, an antibody or fragment thereof comprising a VH domainhaving an amino acid of any of one of the VH domains listed in Table 2is not SYNAGIS®. The present invention also provides antibodies orfragments thereof that immunospecifically bind to one or more RSVantigens, said antibodies or fragments comprising a VH complementaritydetermining region (“CDR”) having an amino acid sequence of any one ofthe VH CDRs listed in Table 2 and/or Table 3. In certain embodiments ofthe invention, an antibody or fragment thereof comprising a VH CDRhaving an amino acid of any of one of the VH CDRs listed in Table 2and/or Table 3 is not SYNAGIS®.

TABLE 2 Antibodies & Fragments Thereof Antibody VH Name VH Chain DomainVH CDR1 VH CDR2 VH CDR3 **SYNAGIS SEQ SEQ ID TSGMSVG DIWWDDKKDYSMITNWYFDV ID NO: NO:7 (SEQ ID NPSLKS (SEQ ID NO:3) 208 NO:1) (SEQ IDNO:2) ***AFFF SEQ SEQ ID T A GMSVG DIWWDDKKDYN SMITN F YFDV ID NO: NO:9(SEQ ID PSLKS (SEQ ID NO:12) 210 NO:10) (SEQ ID NO:2) ***P12f2 SEQ SEQID T P GMSVG DIWWDDKK H YN D MI F N F YFDV ID NO: NO:17 (SEQ ID PSLK D(SEQ ID NO:20) 212 NO:18) (SEQ ID NO:19) ***P12f4 SEQ SEQ ID T P GMSVG DIWWD G KK H YN DMI F NFY F DV ID NO: NO:24 (SEQ ID PSLK D (SEQ ID NO:20)214 NO:18) (SEQ ID NO:25) ***P11d4 SEQ SEQ ID T P GMSVG DIWWD G KK H YND MI F NWYFDV ID NO: NO:28 (SEQ ID PSLK D (SEQ ID NO:29) 216 NO:18) (SEQID NO:25) ***Ale9 SEQ SEQ ID T A GMSVG DIWWD G KK H YN D MI F NWYFDV IDNO: NO:33 (SEQ ID PSLK D (SEQ ID NO:29) 218 NO:10) (SEQ ID NO:25)***A12a6 SEQ SEQ ID T A GMSVG D IWWD G KKDYN DMI F N F YFDV ID NO: NO:36(SEQ ID PSLK D (SEQ ID NO:20) 220 NO:10) (SEQ ID NO:37) ***A13c4 SEQ SEQID T A GMSVG DIWWD G KK S YN D MI F N F YFDV ID NO: NO:40 (SEQ ID PSLK D(SEQ ID NO:20) 222 NO:10) (SEQ ID NO:41) ***A17d4 SEQ SEQ ID T A GMSVGDIWWDDKK S Y D MI F N F YFDV ID NO: NO:44 (SEQ ID NPSLK D (SEQ ID NO:20)224 NO:10) (SEQ ID NO:45) ***A4B4 SEQ SEQ ID T A GMSVG DIWWDDKK H D MI FN F YFDV ID NO: NO:48 (SEQ ID YNPSLK D (SEQ ID NO:20) 226 NO:10) (SEQ IDNO:19) ***A8c7 SEQ SEQ ID T A GMSVG DIWWDDKK S Y D MI F NWYFDV ID NO:NO:51 (SEQ ID NPSLK D (SEQ ID NO:29) 228 NO:10) (SEQ ID NO:45) *1X- SEQSEQ ID TSGMSVG DIWWDDKKDYN SMITNWYFDV 493L1FR ID NO: NO:7 (SEQ ID PSLKS(SEQ ID NO:3) 230 NO:1) (SEQ ID NO:2) *H3-3F4 SEQ SEQ ID T A GMSVGDIWWDDKKDYN D MI F NWYFDV ID NO: NO:55 (SEQ ID PSLKS (SEQ ID NO:29) 232NO:10) (SEQ ID NO:2) *M3H9 SEQ SEQ ID T A GMSVG DIWWDDKKDYN D MI FNWYFDV ID NO: NO:55 (SEQ ID PSLKS (SEQ ID NO:29) 234 NO:10) (SEQ IDNO:2) *Y10H6 SEQ SEQ ID T A GMSVG DIWWDDKKDYN D MI F NWYFDV ID NO: NO:55(SEQ ID PSLKS (SEQ ID NO:29) 236 NO:10) (SEQ ID NO:2) *DG SEQ SEQ ID T AGMSVG DIWWDDKKDYN D MITN F YFDV ID NO: NO:78 (SEQ ID PSLKS (SEQ IDNO:79) 238 NO:10) (SEQ ID NO:2) AFFF(1) SEQ SEQ ID T A GMSVG DIWWDDKKDYNS MITN F YFDV ID NO: NO:9 (SEQ ID PSLKS (SEQ ID NO:12) 240 NO:10) (SEQID NO:2) *6H8 SEQ SEQ ID T A GMSVG DIWWDDKKDYN D MITN F YFDV ID NO:NO:78 (SEQ ID PSLKS (SEQ ID NO:79) 242 NO:10) (SEQ ID NO:2) *L1-7E5 SEQSEQ ID T A GMSVG DIWWDDKKDYN D MITN F YFDV ID NO: NO:78 (SEQ ID PSLKS(SEQ ID NO:79) 244 NO:10) (SEQ ID NO:2) *L2-15B10 SEQ SEQ ID T A GMSVGDIWWDDKKDYN D MITN F YFDV ID NO: NO:78 (SEQ ID PSLKS (SEQ ID NO:79) 246NO:10) (SEQ ID NO:2) *A13a11 SEQ SEQ ID T A GMSVG DIWWDDKK H YN D MI FNWYFDV ID NO: NO:67 (SEQ ID PSLK D (SEQ ID NO:29) 248 NO:10) (SEQ IDNO:19) *A1h5 SEQ SEQ ID T A GMSVG DIWWD G KK H YN D MI F NWYFDV ID NO:NO:33 (SEQ ID PSLK D (SEQ ID NO:29) 250 NO:10) (SEQ ID NO:25) A4B4(1)SEQ SEQ ID T A GMSVG DIWWDDKK H D MI F N F YFDV ID NO: NO:48 (SEQ IDYNPSLK D (SEQ ID NO:20) 252 NO:10) (SEQ ID NO:19) ***A4B4L1 SEQ SEQ ID TA GMSVG DIWWDDKK H D MI F N F YFDV FR-S28R ID NO: NO:48 (SEQ ID YNPSLK D(SEQ ID NO:20) 254 NO:10) (SEQ ID NO:19) ***A4B4- SEQ SEQ ID T A GMSVGDIWWDDKK H YN D MI F N F YFDV F52S ID NO: NO:48 (SEQ ID PSLK D (SEQ IDNO:20) 256 NO:10) (SEQ ID NO:19) Antibody VL VL Name Chain Domain VLCDR1 VL CDR2 VL CDR3 **SYNAGIS SEQ SEQ ID KCQLSVGYMH DTSKLAS FQGSGYPFTID NO: NO:8 (SEQ ID NO:4) (SEQ ID NO:5) (SEQ ID NO:6) 209 ***AFFF SEQSEQ ID SASS SVGYMH DT F KLAS FQ F SGYPFT ID NO: NO:13 (SEQ ID NO:14)(SEQ ID (SEQ ID NO:16) 211 NO:15) ***P12f2 SEQ SEQ ID SLSSR VGYMH DT FYL S S FQGSGYPFT ID NO: NO:21 (SEQ ID NO:22) (SEQ ID (SEQ ID NO:6) 213NO:23) ***P12f4 SEQ SEQ ID SLSSR VGYMH DT RG L P S FQGSGYPFT ID NO:NO:26 (SEQ ID NO:22) (SEQ ID (SEQ ID NO:6) 215 NO:27) ***P11d4 SEQ SEQID SPSSR VGYMH DT MR LAS FQGSGYPFT ID NO: NO:30 (SEQ ID NO:31) (SEQ ID(SEQ ID NO:6) 217 NO:32) ***Ale9 SEQ SEQ ID SLSSR VGYMH DT F KL S SFQGSGYPFT ID NO: NO:34 (SEQ ID NO:22) (SEQ ID (SEQ ID NO:6) 219 NO:35)***A12a6 SEQ SEQ ID SASSR VGYMH DT F KL S S FQGSGYPFT ID NO: NO:38 (SEQID NO:39) (SEQ ID (SEQ ID NO:6) 221 NO:35) ***A13c4 SEQ SEQ ID SLSSRVGYMH DT MYQS S FQGSGYPFT ID NO: NO:42 (SEQ ID NO:22) (SEQ ID (SEQ IDNO:6) 223 NO:43) ***A17d4 SEQ SEQ ID LPSSR VGYMH DT MYQS S FQGSGYPFT IDNO: NO:46 (SEQ ID (SEQ ID (SEQ ID 225 NO:47) NO:43) NO:6) ***A4B4 SEQSEQ ID SASSR VGYMH DT FF L D S FQGSGYPFT ID NO: NO:49 (SEQ ID (SEQ ID(SEQ ID 227 NO:39) NO:50) NO:6) ***A8c7 SEQ SEQ ID SPSSR VGYMH DT RYQS SFQGSGYPFT ID NO: NO:52 (SEQ ID (SEQ ID (SEQ ID 229 NO:31) NO:53) NO:6)*1X- SEQ SEQ ID SASS SVGYMH DTSKLAS FQGSGYPFT 493L1FR ID NO: NO:54 (SEQID NO:14) (SEQ ID NO:5) (SEQ ID NO:6) 231 *H3-3F4 SEQ SEQ ID SASS SVGYMHDT F KLAS FQGSGYPFT ID NO: NO:56 (SEQ ID NO:14) (SEQ ID (SEQ ID NO:6)233 NO:15) *M3H9 SEQ SEQ ID SASS SVGYMH DT Y K QT S FQGSGYPFT ID NO:NO:70 (SEQ ID NO:14) (SEQ ID (SEQ ID NO:6) 235 NO:57) *Y10H6 SEQ SEQ IDSASS SVGYMH DT RY L S S FQGSGYPFT ID NO: NO:58 (SEQ ID NO:14) (SEQ ID(SEQ ID NO:6) 237 NO:59) *DG SEQ SEQ ID SASS SVGYMH DT F KLAS FQGSGYPFTID NO: NO:56 (SEQ ID NO:14) (SEQ ID (SEQ ID NO:6) 239 NO:15) AFFF(1) SEQSEQ ID SASS SVGYMH DT F KLAS FQGS F YPFT ID NO: NO:60 (SEQ ID NO:14)(SEQ ID (SEQ ID NO:61) 241 NO:15) *6H8 SEQ SEQ ID SASS SVGYMH DT F KL TS FQGSGYPFT ID NO: NO:62 (SEQ ID NO:14) (SEQ ID (SEQ ID NO:6) 243 NO:63)*LI-7E5 SEQ SEQ ID SASSR VGYMH DT F KLAS FQGSGYPFT ID NO: NO:64 (SEQ IDNO:39) (SEQ ID (SEQ ID NO:6) 245 NO:15) *L2-15B10 SEQ SEQ ID SASS SVGYMHDT FR LAS FQGSGYPFT ID NO: NO:65 (SEQ ID NO:14) (SEQ ID (SEQ ID NO:6)247 NO:66) *A13a11 SEQ SEQ ID SPSSR VGYMH DT YRHS S FQGSGYPFT ID NO:NO:68 (SEQ ID NO:31) (SEQ ID (SEQ ID NO:6) 249 NO:69) *A1h5 SEQ SEQ IDSLSSS VGYMH DT FFHR S FQGSGYPFT ID NO: NO:71 (SEQ ID NO:72) (SEQ ID (SEQID 251 NO:73) NO:6) A4B4(1) SEQ SEQ ID SASSR VGYMH DT LL L D S FQGSGYPFTID NO: NO:74 (SEQ ID (SEQ ID (SEQ ID 253 NO:39) NO:75) NO:6) ***A4B4L1SEQ SEQ ID SASSR VGYMH DTSKLAS FQGSGYPFT FR-S28R ID NO: NO:11 (SEQ ID(SEQ ID (SEQ ID 255 NO:39) NO:5) NO:6) ***A4B4- SEQ SEQ ID SASSR VGYMHDTS F L D S FQGSGYPFT F52S ID NO: NO:76 (SEQ ID NO:39) (SEQ ID (SEQ IDNO:6) 257 NO:77) Bold faced & underlined amino acid residues are theresidues which differ from the amino acid sequence in SYNAGIS ®; Fabfragment produced (*); Monoclonal antibody produced (**); Fab fragment &monoclonal antibody produced (***)

TABLE 3 CDR Sequences VH CDR1 VH CDR2 VH CDR3 VL CDR1 VL CDR2 VL CDR3 TS GMSVG DIWWD D KK D YNPSLK S S MI T N W YFDV KCQLS VGYMH DT SK L A SFQGSGYPFT (SEQ ID NO:1) (SEQ ID NO:2) (SEQ ID NO:3) (SEQ ID NO:4) (SEQID NO:5) (SEQ ID NO:6) T P GMSVG DIWWDDKK H YNPSLK D D MI T N F YFDVKCQSS VGYMH DT SY L A S FQ F SGYPFT (SEQ ID NO:18) (SEQ ID NO:19) (SEQID NO:29) (SEQ ID NO:80) (SEQ ID NO:81) (SEQ ID NO:6) T A GMSVG DIWWDDKKH YNPSLK S D MI T N W YFDV KCQSR VGYMH DT SY L S S FQGS F YPFT (SEQ IDNO:10) (SEQ ID NO:82) (SEQ ID NO:83) (SEQ ID NO:84) (SEQ ID NO:85) (SEQID NO:61) DIWWD D KK D YNPSLK D D MI F N W YFDV KCQLR VGYMH DT KK L S S(SEQ ID NO:86) (SEQ ID NO:29) (SEQ ID NO:87) (SEQ ID NO:88) DIWWD D KK HYNPSLK S D MI F N F YFDV KLQLS VGYMH DT FY L S S (SEQ ID NO:91) (SEQ IDNO:20) (SEQ ID NO:89) (SEQ ID NO:90) DIWWD D KK D YNPSLK D S MI T N FYFDV KLQSS VGYMH DT FK L A S (SEQ ID NO:93) (SEQ ID NO:12) (SEQ IDNO:92) (SEQ ID NO:15) DIWWD G KK H YNPSLK D S MI F N W YFDV KLQSR VGYMHDT FK L S S (SEQ ID NO:25) (SEQ ID NO:94) (SEQ ID NO:95) (SEQ ID NO:96)DIWWD G KK D YNPSLK S S MI F N F YFDV KLQLR VGYMH DT FY L A S (SEQ IDNO:100) (SEQ ID NO:97) (SEQ ID NO:98) (SEQ ID NO:99) DIWWD G KK D YNPSLKD KLSLS VGYMH DT SK L P S (SEQ ID NO:103) (SEQ ID NO:101) (SEQ IDNO:102) DIWWD G KK H YNPSLK S KLSSS VGYMH DT SG L A S (SEQ ID NO:106)(SEQ ID NO:104) (SEQ ID NO:105) DIWWD D KK S YNPSLK S KLSSR VGYMH DT SGL P S (SEQ ID NO:109) **(SEQ ID NO:107) (SEQ ID NO:108) DIWWD D KK SYNPSLK D KLSLR VGYMH DT RG L P S (SEQ ID NO:111) (SEQ ID NO:110) (SEQ IDNO:27) DIWWD G KK S YNPSLK S KCSLS VGYMH DT RK L A S (SEQ ID NO:114)(SEQ ID NO:112) (SEQ ID NO:113) DIWWD G KK S YNPSLK D KCSSS VGYMH DT RGL A S (SEQ ID NO:41) (SEQ ID NO:115) (SEQ ID NO:116) KCSSR VGYMH DT RK LP S (SEQ ID NO:117) (SEQ ID NO:118) KCSLR VGYMH DT MR L A S (SEQ IDNO:119) (SEQ ID NO:32) SLSLS VGYMH DT MK L A S (SEQ ID NO:120) (SEQ IDNO:121) SLSSS VGYMH DT SR L A S (SEQ ID NO:122) (SEQ ID NO:123) SLSSRVGYMH DT SL L A S (SEQ ID NO:22) (SEQ ID NO:124) SLSLR VGYMH DT SL L D S(SEQ ID NO:125) (SEQ ID NO:126) SCQLS VGYMH DT SK L D S (SEQ ID NO:127)(SEQ ID NO:128) SCQSS VGYMH DT LL L D S (SEQ ID NO:129) (SEQ ID NO:75)SCQSR VGYMH DT LK L D S (SEQ ID NO:130) (SEQ ID NO:131) SCQLR VGYMH DTLL L A S (SEQ ID NO:132) (SEQ ID NO:133) SLQLS VGYMH DT LKLA S (SEQ IDNO:134) (SEQ ID NO:135) SLQSS VGYMH DT SKLS S (SEQ ID NO:136) (SEQ IDNO:137) SLQSR VGYMH DT SKQA S (SEQ ID NO:138) (SEQ ID NO:139) SLQLRVGYMH DT SKQS S (SEQ ID NO:140) (SEQ ID NO:141) SCSLS VGYMH DT SYLA S(SEQ ID NO:142) (SEQ ID NO:143) SCSSS VGYMH DT SYLS S (SEQ ID NO:144)(SEQ ID NO:145) SCSSR VGYMH DT SYQA S (SEQ ID NO:146) (SEQ ID NO:147)SCSLR VGYMH DT SYQS S (SEQ ID NO:148) (SEQ ID NO:149) KPSSR VGYMH DTMYQA S (SEQ ID NO:150) (SEQ ID NO:151) KPSLR VGYMH DT MYQS S (SEQ IDNO:152) (SEQ ID NO:43) KPSSS VGYMH DT MKQA S (SEQ ID NO:153) (SEQ IDNO:154) KPSLS VGYMH DT MKQS S (SEQ ID NO:155) (SEQ ID NO:156) KPQSRVGYMH DT MYLA S (SEQ ID NO:157) (SEQ ID NO:158) KPQLR VGYMH DT MYLS S(SEQ ID NO:159) (SEQ ID NO:160) KPQSS VGYMH DT MKLA S (SEQ ID NO:161)(SEQ ID NO:162) KPQLS VGYMH DT MKLS S (SEQ ID NO:163) (SEQ ID NO:164)SPSSR VGYMH DT SK L S S (SEQ ID NO:31) (SEQ ID NO:165) SPSLR VGYMH DTRYQA S (SEQ ID NO:166) (SEQ ID NO:167) SPSSS VGYMH DT RYQS S (SEQ IDNO:168) (SEQ ID NO:53) SPSLS VGYMH DT RKQA S (SEQ ID NO:169) (SEQ IDNO:170) SPQSR VGYMH DT RKQS S (SEQ ID NO:171) (SEQ ID NO:172) SPQLRVGYMH DT RKLA S (SEQ ID NO:173) (SEQ ID NO:174) SPQSS VGYMH DT RKLS S(SEQ ID NO:175) (SEQ ID NO:176) SPQLS VGYMH DT RYLA S (SEQ ID NO:177)(SEQ ID NO:178) KAQSR VGYMH DT RYLS S (SEQ ID NO:179) (SEQ ID NO:59)KAQLR VGYMH DT FF L D S (SEQ ID NO:180) (SEQ ID NO:50) KAQSS VGYMH DTS FL D S (SEQ ID NO:181) (SEQ ID NO:77) KAQLS VGYMH (SEQ ID NO:182) KASSRVGYMH (SEQ ID NO:183) KASLR VGYMH (SEQ ID NO:184) KASSS VGYMH (SEQ IDNO:185) KASLS VGYMH (SEQ ID NO:186) SASSR VGYMH (SEQ ID NO:39) SASLRVGYMH (SEQ ID NO:187) SASSS VGYMH (SEQ ID NO:14) SASLS VGYMH (SEQ IDNO:188) SAQSR VGYMH (SEQ ID NO:189) SAQLR VGYMH (SEQ ID NO:190) SAQSSVGYMH (SEQ ID NO:191) LPSSR VGYMH (SEQ ID NO:47) LPSLS VGYMH (SEQ IDNO:192) LPSSS VGYMH (SEQ ID NO:193) LPSLR VGYMH (SEQ ID NO:194) LCSSRVGYMH (SEQ ID NO:195) LCSLS VGYMH (SEQ ID NO:196) LCSSS VGYMH (SEQ IDNO:197) LCSLR VGYMH (SEQ ID NO:198) LPQSR VGYMH (SEQ ID NO:199) LPQLSVGYMH (SEQ ID NO:200) LPQSS VGYMH (SEQ ID NO:201) LPQLR VGYMH (SEQ IDNO:202) LCQSR VGYMH (SEQ ID NO:203) LCQLS VGYMH (SEQ ID NO:204) LCQSSVGYMH (SEQ ID NO:205) LCQLR VGYMH (SEQ ID NO:206) SAQLS VGYMH (SEQ IDNO:207)

In one embodiment of the present invention, antibodies or fragmentsthereof comprise a VH CDR1 having the amino acid sequence of SEQ IDNO:1, SEQ ID NO:10 or SEQ ID NO:18. In another embodiment, antibodies orfragments thereof comprise a VH CDR2 having the amino acid sequence ofSEQ ID NO:2, SEQ ID NO:19, SEQ ID NO:25, SEQ ID NO:37, SEQ ID NO:41 orSEQ ID NO:45. In another embodiment, antibodies comprise a VH CDR3having the amino acid sequence of SEQ ID NO:3, SEQ ID NO:12, SEQ IDNO:20, SEQ ID NO:29 or SEQ ID NO:79. In a preferred embodiment,antibodies or fragments thereof comprise a VH CDR1 having the amino acidsequence of SEQ ID NO:1, SEQ ID NO:10 or SEQ ID NO:18, a VH CDR2 havingthe amino acid sequence of SEQ ID NO:2, SEQ ID NO:19, SEQ ID NO:25, SEQID NO:37 or SEQ ID NO:41, SEQ ID NO:45, and a VH CDR3 having the aminoacid sequence of SEQ ID NO:3, SEQ ID NO:12, SEQ ID NO:20, SEQ ID NO:29or SEQ ID NO:79.

The present invention also provides antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens, said antibodies orantibody fragments comprising a variable light (“VL”) domain having anamino acid sequence of any one of the VL domains listed in Table 2. Thepresent invention also provides antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens, said antibodies orfragments comprising a VL CDR having an amino acid sequence of any oneof the VL CDRs listed in Table 2 and/or Table 3.

In one embodiment of the present invention, antibodies or fragmentsthereof comprise a VL CDR1 having the amino acid sequence of SEQ IDNO:4, SEQ ID NO:14, SEQ ID NO:22, SEQ ID NO:31, SEQ ID NO:39, or SEQ IDNO:47. In another embodiment, antibodies or fragments thereof comprise aVL CDR2 having the amino acid sequence of SEQ ID NO:5, SEQ ID NO:15, SEQID NO:23, SEQ ID NO:27, SEQ ID NO:32, SEQ ID NO:35, SEQ ID NO:43, SEQ IDNO:50, SEQ ID NO:53, SEQ ID NO:57, SEQ ID NO:59, SEQ ID NO:63, SEQ IDNO:66, SEQ ID NO:69, SEQ ID NO:73, SEQ ID NO:75 or SEQ ID NO:77. Inanother embodiment, antibodies or fragments thereof comprise a VL CDR3having the amino acid sequence of SEQ ID NO:6, SEQ ID NO:16 or SEQ IDNO:61. In a preferred embodiment, antibodies or fragments thereofcomprise a VL CDR1 having the amino acid sequence of SEQ ID NO:4, SEQ IDNO:14, SEQ ID NO:22, SEQ ID NO:31, SEQ ID NO:39, or SEQ ID NO:47, a VLCDR2 having the amino acid sequence of SEQ ID NO:5, SEQ ID NO:15, SEQ IDNO:23, SEQ ID NO:27, SEQ ID NO:32, SEQ ID NO:35, SEQ ID NO:43, SEQ IDNO:50, SEQ ID NO:53, SEQ ID NO:57, SEQ ID NO:59, SEQ ID NO:63, SEQ IDNO:66, SEQ ID NO:69, SEQ ID NO:73, SEQ ID NO:75 or SEQ ID NO:77, and aVL CDR3 having the amino acid sequence of SEQ ID NO:6, SEQ ID NO:16 orSEQ ID NO:61.

The present invention also provides antibodies or fragments thereof thatimmunospecifically bind to one or more RSV antigens, said antibodies orantibody fragments comprising a VH domain disclosed herein combined witha VL domain disclosed herein, or other VL domain. The present inventionfurther provides antibodies or fragments thereof that immunospecificallybind to one or more RSV antigens, said antibodies or fragmentscomprising a VL domain disclosed herein combined with a VH domaindisclosed herein, or other VH domain. In a preferred embodiment,antibodies or fragments thereof that immunospecifically bind to a RSVantigen comprise a VH domain having the amino acid sequence of SEQ IDNO:7, SEQ ID NO:9, SEQ ID NO:17, SEQ ID NO:24, SEQ ID NO:28, SEQ IDNO:33, SEQ ID NO:36, SEQ ID NO:40, SEQ ID NO:44, SEQ ID NO:48, SEQ IDNO:51, SEQ ID NO:55, SEQ ID NO:67 or SEQ ID NO:78 and a VL domain havingthe amino acid sequence of SEQ ID NO:8, SEQ ID NO:13, SEQ ID NO:21, SEQID NO:26, SEQ ID NO:30, SEQ ID NO:34, SEQ ID NO:38, SEQ ID NO:42, SEQ IDNO:46, SEQ ID NO:49, SEQ ID NO:52, SEQ ID NO:54, SEQ ID NO:56, SEQ IDNO:58, SEQ ID NO:60, SEQ ID NO:62, SEQ ID NO:64, SEQ ID NO:65, SEQ IDNO:68, SEQ ID NO:70, SEQ ID NO:71, SEQ ID NO:74 or SEQ ID NO:76.

The present invention also provides antibodies or fragments thereofcomprising one or more VH CDRs and one or more VL CDRs listed in Table 2and/or Table 3. In particular, the invention provides for an antibody orfragment thereof comprising a VH CDR1 and a VL CDR1, a VH CDR1 and a VLCDR2, a VH CDR1 and a VL CDR3, a VH CDR2 and a VL CDR1, VH CDR2 and VLCDR2, a VH CDR2 and a VL CDR3, a VH CDR3 and a VH CDR1, a VH CDR3 and aVL CDR2, a VH CDR3 and a VL CDR3, or any combination thereof of the VHCDRs and VL CDRs listed in Table 2. The invention also provides for anantibody or fragment thereof comprising a VH CDR1 and a VL CDR1, a VHCDR1 and a VL CDR2, a VH CDR1 and a VL CDR3, a VH CDR2 and a VL CDR1, VHCDR2 and VL CDR2, a VH CDR2 and a VL CDR3, a VH CDR3 and a VH CDR1, a VHCDR3 and a VL CDR2, a VH CDR3 and a VL CDR3, or any combination thereofof the VH CDRs and VL CDRs listed in Table 3. The invention alsoprovides for an antibody or fragment thereof comprising a VH CDR1 and aVL CDR1, a VH CDR1 and a VL CDR2, a VH CDR1 and a VL CDR3, a VH CDR2 anda VL CDR1, VH CDR2 and VL CDR2, a VH CDR2 and a VL CDR3, a VH CDR3 and aVH CDR1, a VH CDR3 and a VL CDR2, a VH CDR3 and a VL CDR3, or anycombination thereof of the VH CDRs and VL CDRs listed in Table 2 andTable 3.

In one embodiment, an antibody or fragment thereof comprises a VH CDR1having the amino acid sequence of SEQ ID NO:1, SEQ ID NO:10 or SEQ IDNO:18 and a VL CDR1 having the amino acid sequence of SEQ ID NO:4, SEQID NO:14, SEQ ID NO:22, SEQ ID NO:31, SEQ ID NO:39, or SEQ ID NO:47. Inanother embodiment, an antibody of the present invention or fragmentthereof comprises a VH CDR1 having the amino acid sequence of SEQ IDNO:1, SEQ ID NO:10 or SEQ ID NO:18 and a VL CDR2 having the amino acidsequence of SEQ ID NO:5, SEQ ID NO:15, SEQ ID NO:23, SEQ ID NO:27, SEQID NO:32, SEQ ID NO:35, SEQ ID NO:43, SEQ ID NO:50, SEQ ID NO:53, SEQ IDNO:57, SEQ ID NO:59, SEQ ID NO:63, SEQ ID NO:66, SEQ ID NO:69, SEQ IDNO:73, SEQ ID NO:75, or SEQ ID NO:77. In another embodiment, an antibodyof the present invention or fragment thereof comprises a VH CDR1 havingthe amino acid sequence of SEQ ID NO:1, SEQ ID NO:10 or SEQ ID NO:18 anda VL CDR3 having the amino acid sequence of SEQ ID NO:6, SEQ ID NO:16 orSEQ ID NO:61.

In another embodiment, an antibody of the present invention or fragmentthereof comprises a VH CDR2 having the amino acid sequence of SEQ IDNO:2, SEQ ID NO:19, SEQ ID NO:25, SEQ ID NO:37, SEQ ID NO:41 or SEQ IDNO:45 and a VL CDR1 having the amino acid sequence of SEQ ID NO:4, SEQID NO:14, SEQ ID NO:22, SEQ ID NO:31, SEQ ID NO:39 or SEQ ID NO:47. Inanother embodiment, an antibody of the present invention or fragmentthereof comprises a VH CDR2 having the amino acid sequence of SEQ IDNO:2, SEQ ID NO:19, SEQ ID NO:25, SEQ ID NO:37, SEQ ID NO:41 or SEQ IDNO:45 and a VL CDR2 having the amino acid sequence of SEQ ID NO:5, SEQID NO:15, SEQ ID NO:23, SEQ ID NO:27, SEQ ID NO:32, SEQ ID NO:35, SEQ IDNO:43, SEQ ID NO:50, SEQ ID NO:53, SEQ ID NO:57, SEQ ID NO:59, SEQ IDNO:63, SEQ ID NO:66, SEQ ID NO:69, SEQ ID NO:73, SEQ ID NO:75, or SEQ IDNO:77. In another embodiment, an antibody of the present invention orfragment thereof comprises a VH CDR2 having the amino acid sequence ofSEQ ID NO:2, SEQ ID NO:19, SEQ ID NO:25, SEQ ID NO:37, SEQ ID NO:41 orSEQ ID NO:45 and a VL CDR3 having the amino acid sequence of SEQ IDNO:6, SEQ ID NO:16, or SEQ ID NO:61.

In another embodiment, an antibody of the present invention or fragmentthereof comprises a VH CDR3 having the amino acid sequence of SEQ IDNO:3, SEQ ID NO:12, SEQ ID NO:20, SEQ ID NO:29 or SEQ ID NO:79 and a VLCDR1 having the amino acid sequence of SEQ ID NO:4, SEQ ID NO:14, SEQ IDNO:22, SEQ ID NO:31, SEQ ID NO:39 or SEQ ID NO:47. In anotherembodiment, an antibody of the present invention or fragment thereofcomprises a VH CDR3 having the amino acid sequence of SEQ ID NO:3, SEQID NO:12, SEQ ID NO:20, SEQ ID NO:29 or SEQ ID NO:79 and a VL CDR havingthe amino acid sequence of SEQ ID NO:5, SEQ ID NO:15, SEQ ID NO:23, SEQID NO:27, SEQ ID NO:32, SEQ ID NO:35, SEQ ID NO:43, SEQ ID NO:50, SEQ IDNO:53, SEQ ID NO:57, SEQ ID NO:59, SEQ ID NO:63, SEQ ID NO:66, SEQ IDNO:69, SEQ ID NO:73, SEQ ID NO:75, or SEQ ID NO:77. In a preferredembodiment, an antibody of the present invention or fragment thereofcomprises a VH CDR3 having the amino acid sequence of SEQ ID NO:3, SEQID NO:12, SEQ ID NO:20, SEQ ID NO:29 or SEQ ID NO:79 and a VL CDR3having the amino acid sequence of SEQ ID NO:6, SEQ ID NO:16, or SEQ IDNO:61.

The present invention also provides for nucleic acid molecules,generally isolated, encoding an antibody of the invention or fragmentthereof. In a specific embodiment, isolated nucleic acid molecules ofthe invention encode for SYNAGIS®, AFFF, Pf12, P12f4, P11d4, A1e9,A12a6, A13c4, A17d4, A4B4, A8C7, 1X-493L1FR, H3-3F4, M3H9, Y10H6, DG,AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, orA4B4-F52S. Preferably, isolated nucleic acid molecules of the inventionencode for AFFF, Pf12, P12f4, P11d4, A1e9, A12a6, A13c4, A17d4, A4B4,A8C7, 1X-493L1FR, H3-3F4, M3H9, Y10H6, DG, AFFF(1), 6H8, L1-7E5,L2-15B10, A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, or A4B4-F52S. In anotherembodiment, isolated nucleic acid molecules of the invention encode foran antigen-binding fragment of SYNAGIS(V, AFFF, Pf12, P12f4, P11d4,A1e9, A12a6, A13c4, A17d4, A4B4, A8C7, 1X-493L1FR, H3-3F4, M3H9, Y10H6,DG, AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1),A4B4L1FR-S28R, or A4B4-F52S.

In another embodiment, an isolated nucleic acid molecule(s) of theinvention encodes an antibody or fragment thereof comprising a VH domainhaving an amino acid sequence of any one of the VH domains listed inTable 2. In another embodiment, an isolated nucleic acid molecule(s) ofthe invention encodes an antibody or fragment thereof comprising a VHCDR1 having an amino acid sequence of any one of the VH CDR1s listed inTable 2 or Table 3. In another embodiment, an isolated nucleic acidmolecule(s) of the invention encodes an antibody or fragment thereofcomprising a VH CDR2 having an amino acid sequence of any one of the VHCDR2s listed in Table 2 or Table 3. In yet another embodiment, anisolated nucleic acid molecule(s) of the invention encodes an antibodyor fragment thereof comprising a VH CDR3 having an amino acid sequenceof any one of the VH CDR3s listed in Table 2 or Table 3.

In another embodiment, an isolated nucleic acid molecule(s) of theinvention encodes an antibody or fragment thereof comprising a VL domainhaving an amino acid sequence of any one of the VL domains listed inTable 2. In another embodiment, an isolated nucleic acid molecule(s) ofthe present invention encodes an antibody or fragment thereof comprisinga VL CDR1 having amino acid sequence of any one of the VL CDR1s listedin Table 2 or Table 3. In another embodiment, an isolated nucleic acidmolecule(s) of the present invention encodes an antibody or fragmentthereof comprising a VL CDR2 having an amino acid sequence of any one ofthe VL CDR2s listed in Table 2 or Table 3. In yet another embodiment, anisolated nucleic acid molecule(s) of the present invention encodes anantibody or fragment thereof comprising a VL CDR3 having an amino acidsequence of any one of the VL CDR3s listed in Table 2 or Table 3.

In another embodiment, a nucleic acid molecule(s) of the inventionencodes an antibody or fragment thereof comprising a VH domain having anamino acid sequence of any one of the VH domains listed in Table 2 and aVL domain having an amino acid sequence of any one of the VL domainslisted in Table 2. In another embodiment, a nucleic acid molecule(s) ofthe invention encodes an antibody or fragment thereof comprising a VHCDR1, a VL CDR1, a VH CDR2, a VL CDR2, a VH CDR3, a VL CDR3, or anycombination thereof having an amino acid sequence listed in Table 2. Inanother embodiment, a nucleic acid molecule(s) of the invention encodesan antibody or fragment thereof comprising a VH CDR1, a VL CDR1, a VHCDR2, a VL CDR2, a VH CDR3, a VL CDR3, or any combination thereof havingan amino acid sequence listed in Table 3. In another embodiment, anucleic acid molecule(s) of the invention encodes an antibody orfragment thereof comprising a VH CDR1, a VL CDR1, a VH CDR2, a VL CDR2,a VH CDR3, a VL CDR3, or any combination thereof having an amino acidsequence listed in Table 2 and Table 3.

The present invention also provides antibodies or fragments thereofcomprising derivatives of the VH domains, VH CDRs, VL domains, and VLCDRs described herein that immunospecifically bind to an RSV antigen.The present invention also provides antibodies or fragments thereofcomprising derivatives of SYNAGIS®, AFFF, Pf12, P12f4, P11d4, A1e9,A12a6, A13c4, A17d4, A4B4, A8C7, 1X-493L1FR, H3-3F4, M3H9, Y10H6, DG,AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, orA4B4-F52S, wherein said antibodies or fragments thereofimmunospecifically bind to one or more RSV antigens. Standard techniquesknown to those of skill in the art can be used to introduce mutations inthe nucleotide sequence encoding a molecule of the invention, including,for example, site-directed mutagenesis and PCR-mediated mutagenesiswhich results in amino acid substitutions. Preferably, the derivativesinclude less than 25 amino acid substitutions, less than 20 amino acidsubstitutions, less than 15 amino acid substitutions, less than 10 aminoacid substitutions, less than 5 amino acid substitutions, less than 4amino acid substitutions, less than 3 amino acid substitutions, or lessthan 2 amino acid substitutions relative to the original molecule. In apreferred embodiment, the derivatives have conservative amino acidsubstitutions are made at one or more predicted non-essential amino acidresidues. A “conservative amino acid substitution” is one in which theamino acid residue is replaced with an amino acid residue having a sidechain with a similar charge. Families of amino acid residues having sidechains with similar charges have been defined in the art. These familiesinclude amino acids with basic side chains (e.g., lysine, arginine,histidine), acidic side chains (e.g., aspartic acid, glutamic acid),uncharged polar side chains (e.g., glycine, asparagine, glutamine,serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g.,alanine, valine, leucine, isoleucine, proline, phenylalanine,methionine, tryptophan), beta-branched side chains (e.g., threonine,valine, isoleucine) and aromatic side chains (e.g., tyrosine,phenylalanine, tryptophan, histidine). Alternatively, mutations can beintroduced randomly along all or part of the coding sequence, such as bysaturation mutagenesis, and the resultant mutants can be screened forbiological activity to identify mutants that retain activity. Followingmutagenesis, the encoded protein can be expressed and the activity ofthe protein can be determined.

In a specific embodiment, an antibody or fragment thereof thatimmunospecifically binds to a RSV antigen comprises a nucleotidesequence that hybridizes to the nucleotide sequence(s) encodingSYNAGIS®, AFFF, Pf12, P12f4, P11d4, A1e9, A12a6, A13c4, A17d4, A4B4,A8C7, 1X-493L1FR, H3-3F4, M3H9, Y10H6, DG, AFFF(1), 6H8, L1-7E5,L2-15B10, A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, or A4B4-F52S understringent conditions, e.g., hybridization to filter-bound DNA in 6×sodium chloride/sodium citrate (SSC) at about 45° C. followed by one ormore washes in 0.2×SSC/0.1% SDS at about 50-65° C., under highlystringent conditions, e.g., hybridization to filter-bound nucleic acidin 6×SSC at about 45° C. followed by one or more washes in 0.1×SSC/0.2%SDS at about 68° C., or under other stringent hybridization conditionswhich are known to those of skill in the art (see, for example, Ausubel,F. M. et al., eds., 1989, Current Protocols in Molecular Biology, Vol.1, Green Publishing Associates, Inc. and John Wiley & Sons, Inc., NewYork at pages 6.3.1-6.3.6 and 2.10.3).

In another embodiment, an antibody or fragment thereof thatimmunospecifically binds to a RSV antigen comprises an amino acidsequence that is at least 35%, at least 40%, at least 45%, at least 50%,at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, atleast 80%, at least 85%, at least 90%, at least 95%, or at least 99%identical to the amino acid sequence of SYNAGIS®, AFFF, Pf12, P12f4,P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8C7, 1X-493L1FR, H3-3F4, M3H9,Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1),A4B4L1FR-S28R, or A4B4-F52S.

In a specific embodiment, an antibody or fragment thereof thatimmunospecifically binds to a RSV antigen comprises an amino acidsequence of a VH domain or an amino acid sequence a VL domain encoded bya nucleotide sequence that hybridizes to the nucleotide sequenceencoding any one of the VH or VL domains listed in Table 2 understringent conditions, e.g., hybridization to filter-bound DNA in 6×sodium chloride/sodium citrate (SSC) at about 45° C. followed by one ormore washes in 0.2×SSC/0.1% SDS at about 50-65° C., under highlystringent conditions, e.g., hybridization to filter-bound nucleic acidin 6×SSC at about 45° C. followed by one or more washes in 0.1×SSC/0.2%SDS at about 68° C., or under other stringent hybridization conditionswhich are known to those of skill in the art (see, for example, Ausubel,F. M. et al., eds., 1989, Current Protocols in Molecular Biology, Vol.I, Green Publishing Associates, Inc. and John Wiley & Sons, Inc., NewYork at pages 6.3.1-6.3.6 and 2.10.3). In another embodiment, anantibody or fragment thereof that immunospecifically binds to a RSVantigen comprises an amino acid sequence of a VH CDR or an amino acidsequence of a VL CDRs encoded by a nucleotide sequence that hybridizesto the nucleotide sequence encoding any one of the VH CDRs or VL CDRslisted in Table 2 or Table 3 under stringent conditions e.g.,hybridization to filter-bound DNA in 6× sodium chloride/sodium citrate(SSC) at about 45° C. followed by one or more washes in 0.2×SSC/0.1% SDSat about 50-65° C., under highly stringent conditions, e.g.,hybridization to filter-bound nucleic acid in 6×SSC at about 45° C.followed by one or more washes in 0.1×SSC/0.2% SDS at about 68° C., orunder other stringent hybridization conditions which are known to thoseof skill in the art. In yet another embodiment, an antibody or fragmentthereof that immunospecifically binds to a RSV antigen comprises anamino acid sequence of a VH CDR and an amino acid sequence of a VL CDRencoded by nucleotide sequences that hybridizes to the nucleotidesequences encoding any one of the VH CDRs and VL CDRs, respectively,listed in Table 2 or Table 3 under stringent conditions, e.g.,hybridization to filter-bound DNA in 6× sodium chloride/sodium citrate(SSC) at about 45° C. followed by one or more washes in 0.2×SSC/0.1% SDSat about 50-65° C., under highly stringent conditions, e.g.,hybridization to filter-bound nucleic acid in 6×SSC at about 45° C.followed by one or more washes in 0.1×SSC/0.2% SDS at about 68° C., orunder other stringent hybridization conditions which are known to thoseof skill in the art.

In another embodiment, an antibody or fragment thereof thatimmunospecifically 35 binds to a RSV antigen comprises an amino acidsequence of a VH domain that is at least 35%, at least 40%, at least45%, at least 50%, at least 55%, at least 60%, at least 65%, at least70%, at least 75%, at least 80%, at least 85%, at least 90%, at least95%, or at least 99% identical to any one of the VH domains listed inTable 2. In another embodiment, an antibody or fragment thereof thatimmunospecifically binds to a RSV antigen comprises an amino acidsequence of one or more VH CDRs that are at least 35%, at least 40%, atleast 45%, at least 50%, at least 55%, at least 60%, at least 65%, atleast 70%, at least 750/0, at least 80%, at least 85%, at least 90%, atleast 95%, or at least 99% identical to any of the VH CDRs listed inTable 2 or Table 3.

In another embodiment, an antibody or fragment thereof thatimmunospecifically binds to a RSV antigen comprises an amino acidsequence of a VL domain that is at least 35%, at least 40%, at least45%, at least 50%, at least 55%, at least 60%, at least 65%, at least70%, at least 75%, at least 80%, at least 85%, at least 90%, at least95%, or at least 99% identical to any one of the VL domains listed inTable 2. In another embodiment, an antibody or fragment thereof thatimmunospecifically binds to a RSV antigen comprises an amino acidsequence of one or more VL CDRs that are at least 35%, at least 40%, atleast 45%, at least 50%, at least 55%, at least 60%, at least 65%, atleast 70%, at least 7501%, at least 80%, at least 85%, at least 90%, atleast 95%, or at least 99% identical to any of the VL CDRs listed inTable 2 or Table 3.

In another embodiment, an antibody or fragment thereof thatimmunospecifically binds to a RSV antigen comprises an amino acidsequence that is at least 35%, at least 40%, at least 45%, at least 50%,at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, atleast 80%, at least 85%, at least 90%, at least 95%, or at least 99%identical to an amino acid sequence of SYNAGIS®, AFFF, Pf12, P12f4,P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8C7, 1X-493L1FR, H3-3F4, M3H9,Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1),A4B4L1FR-S28R, or A4B4-F52S The present invention also encompassesantibodies or fragments thereof that compete with an antibody or Fabfragment listed in Table 2 for binding to a RSV antigen.

In particular, the present invention encompasses antibodies or fragmentsthereof that compete with SYNAGIS® or an antigen-binding fragmentthereof for binding to the RSV F glycoprotein. The present inventionalso encompasses VL domains, VH domains, VL CDRs, and VH CDRs thatcompete with a VL domain, VH domain, VL CDR, or VH CDR listed in Table 2for binding to a RSV antigen. Further, the present invention encompassesVL CDRs and VL CDRs that compete with a VL CDR or VH CDR listed in Table3 for binding to a RSV antigen.

The antibodies of the invention include derivatives that are modified,i.e, by the covalent attachment of any type of molecule to the antibodysuch that covalent attachment For example, but not by way of limitation,the antibody derivatives include antibodies that have been modified,e.g, by glycosylation, acetylation, pegylation, phosphorylation,amidation, derivatization by known protecting/blocking groups,proteolytic cleavage, linkage to a cellular ligand or other protein,etc. Any of numerous chemical modifications may be carried out by knowntechniques, including, but not limited to specific chemical cleavage,acetylation, formylation, metabolic synthesis of tunicamycin, etc.Additionally, the derivative may contain one or more non-classical aminoacids.

The present invention also provides antibodies of the invention orfragments thereof that comprise a framework region known to those ofskill in the art. Preferably, the framework region of an antibody of theinvention or fragment thereof is human. In a specific embodiment, anantibody of the invention or fragment thereof comprises the frameworkregion of SYNAGIS®.

The present invention also provides antibodies of the invention orfragments thereof that comprise constant regions known to those of skillin the art. Preferably, the constant regions of an antibody of theinvention or fragment thereof are human. In a specific embodiment, anantibody of the invention or fragment thereof comprises the constantregions of SYNAGIS®.

The present invention also provides for antibodies or fragments thereofthat have half-lives in a mammal, preferably a human, of greater than 15days, preferably greater than 20 days, greater than 25 days, greaterthan 30 days, greater than 35 days, greater than 40 days, greater than45 days, greater than 2 months, greater than 3 months, greater than 4months, or greater than 5 months. The increased half-lives of theantibodies of the present invention or fragments thereof in a mammal,preferably a human, results in a higher serum titer of said antibodiesor antibody fragments in the mammal, and thus, reduces the frequency ofthe administration of said antibodies or antibody fragments and/orreduces the concentration of said antibodies or antibody fragments to beadministered. Antibodies or fragments thereof having increased in vivohalf-lives can be generated by techniques known to those of skill in theart. For example, antibodies or fragments thereof with increased in vivohalf-lives can be generated by modifying (e.g., substituting, deletingor adding) amino acid residues identified as involved in the interactionbetween the Fc domain and the FcRn receptor (see, e.g., PCT PublicationNo. WO 97/34631, which is incorporated herein by reference in itsentirety). Such antibodies or fragments thereof can be tested forbinding activity to RSV antigens as well as for in vivo efficacy usingmethods known to those skilled in the art, for example, by immunoassaysdescribed herein.

Further, antibodies or fragments thereof with increased in vivohalf-lives can be generated by attaching to said antibodies or antibodyfragments polymer molecules such as high molecular weightpolyethyleneglycol (PEG). PEG can be attached to said antibodies orantibody fragments with or without a multifunctional linker eitherthrough site-specific conjugation of the PEG to the N- or C-terminus ofsaid antibodies or antibody fragments or via epsilon-amino groupspresent on lysine residues. Linear or branched polymer derivatizationthat results in minimal loss of biological activity will be used. Thedegree of conjugation will be closely monitored by SDS-PAGE and massspectrometry to ensure proper conjugation of PEG molecules to theantibodies. Unreacted PEG can be separated from antibody-PEG conjugatesby, e.g., size exclusion or ion-exchange chromatography.PEG-derivatizated antibodies or fragments thereof can be tested forbinding activity to RSV antigens as well as for in vivo efficacy usingmethods known to those skilled in the art, for example, by immunoassaysdescribed herein.

The present invention also encompasses antibodies or fragments thereofwhich immunospecifically bind to one or more RSV antigens, saidantibodies or antibody fragments comprising the amino acid sequence ofSYNAGIS® with mutations (e.g., one or more amino acid substitutions) inthe framework regions. In certain embodiments, antibodies or fragmentsthereof which immunospecifically bind to one or more RSV antigenscomprise the amino acid sequence of SYNAGIS® with one or more amino acidresidue substitutions in the framework regions of the VH and/or VLdomains depicted in FIG. 1. In a specific embodiment, antibodies orfragments thereof which immunospecifically bind to one or more RSVantigens comprise the framework regions depicted in FIG. 2.

The present invention also encompasses antibodies or fragments thereofwhich immunospecifically bind to one or more RSV antigens, saidantibodies or fragments thereof comprising the amino acid sequence ofSYNAGIS® with mutations (e.g., one or more amino acid residuesubstitutions) in the variable and framework regions.

The present invention also provides for fusion proteins comprising anantibody or fragment thereof that immunospecifically binds to a RSVantigen and a heterologous polypeptide. Preferably, the heterologouspolypeptide that the antibody or antibody fragment is fused to is usefulfor targeting the antibody to respiratory epithelial cells.

The present invention also provides for panels of antibodies orfragments thereof that immunospecifically bind to an RSV antigen. Inspecific embodiments, the invention provides for panels of antibodies orfragments thereof having different affinities for an RSV antigen,different specificities for an RSV antigen, or different dissociationrates. The invention provides panels of at least 10, preferably at least25, at least 50, at least 75, at least 100, at least 125, at least 150,at least 175, at least 200, at least 250, at least 300, at least 350, atleast 400, at least 450, at least 500, at least 550, at least 600, atleast 650, at least 700, at least 750, at least 800, at least 850, atleast 900, at least 950, or at least 1000 antibodies or fragmentsthereof. Panels of antibodies can be used, for example, in 96 wellplates for assays such as ELISAs.

The present invention further provides for compositions comprising oneor more antibodies of the invention or fragments thereof. In a specificembodiment, a composition of the present invention comprises SYNAGIS®,AFFF, Pf12, P12f4, P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8C7,1X-493L1FR, H3-3F4, M3H9, Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10,A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, and/or A4B4-F52S. In anotherspecific embodiment, a composition of the present invention comprises anantigen-binding fragment of SYNAGIS®, AFFF, Pf12, P12f4, P11d4, A1e9,A12a6, A13c4, A17d4, A4B4, A8C7, 1X-493L1FR, H3-3F4, M3H9, Y10H6, DG,AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, orA4B4-F52S.

In another embodiment, a composition of the present invention comprisesone or more antibodies or fragments thereof comprising one or more VHdomains having an amino acid sequence of any one of the VH domainslisted in Table 2. In another embodiment, a composition of the presentinvention comprises one or more antibodies or fragments thereofcomprising one or more VH CDR1s having an amino acid sequence of any oneof the VH CDR1s listed in Table 2 or Table 3. In another embodiment, acomposition of the present invention comprises one or more antibodies orfragments thereof comprising one or more VH CDR2s having an amino acidsequence of any one of the VH CDR2s listed in Table 2 or Table 3. In apreferred embodiment, a composition of the present invention comprisesone or more antibodies or fragments thereof comprising one or more VHCDR3s having an amino acid sequence of any one of the VH CDR3s listed inTable 2 or Table 3.

In another embodiment, a composition of the present invention comprisesone or more antibodies or fragments thereof comprising one or more VLdomains having an amino acid sequence of any one of the VL domainslisted in Table 2. In another embodiment, a composition of the presentinvention comprises one or more antibodies or fragments thereofcomprising one or more VL CDR1s having an amino acid sequence of any oneof the VH CDR1s listed in Table 2 or Table 3. In another embodiment, acomposition of the present invention comprises one or more antibodies orfragments thereof comprising one or more VL CDR2s having an amino acidsequence of any one of the VL CDR2s listed in Table 2 or Table 3. In apreferred embodiment, a composition of the present invention comprisesone or more antibodies or fragments thereof comprising one or more VLCDR3s having an amino acid sequence of any one of the VL CDR3s listed inTable 2 or Table 3.

In another embodiment, a composition of the present invention comprisesone or more antibodies or fragments thereof comprising one or more VHdomains having an amino acid sequence of any one of the VH domainslisted in Table 2 and one or more VL domains having an amino acidsequence of any one of the VL domains listed in Table 2. In anotherembodiment, a composition of the present invention comprises one or moreantibodies or fragments thereof comprising one or more VH CDR1s havingan amino acid sequence of any one of the VH CDR1s listed in Table 2 orTable 3 and one or more VL CDR1s having an amino acid sequence of anyone of the VL CDR1s listed in Table 2 or Table 3. In another embodiment,a composition of the present invention comprises one or more antibodiesor fragments thereof comprising one or more VH CDR1s having an aminoacid sequence of any one of the VH CDR1s listed in Table 2 or Table 3and one or more VL CDR2s having an amino acid sequence of any one of theVL CDR2s listed in Table 2 or Table 3. In another embodiment, acomposition of the present invention comprises one or more antibodies orfragments thereof comprising one or more VH CDR1s having an amino acidsequence of any one of the VH CDR1s listed in Table 2 or Table 3 and oneor more VL CDR3s having an amino acid sequence of any one of the VLCDR3s listed in Table 2 or Table 3.

In another embodiment, a composition of the present invention comprisesone or more antibodies or fragments thereof comprising one or more VHCDR2s having an amino acid sequence of any one of the VH CDR2s listed inTable 2 or Table 3 and one or more VL CDR1s having an amino acidsequence of any one of the VL CDR1s listed in Table 2 or Table 3. Inanother embodiment, a composition of the present invention comprises oneor more antibodies or fragments thereof comprising one or more VH CDR2shaving an amino acid sequence of any one of the VH CDR2s listed in Table2 or Table 3 and one or more VL CDR2s having an amino acid sequence ofany one of the VL CDR2s listed in Table 2 or Table 3. In anotherembodiment, a composition of the present invention comprises one or moreantibodies or fragments thereof comprising one or more VH CDR2s havingan amino acid sequence of any one of the VH CDR2s listed in Table 2 orTable 3 and one or more VL CDR3s having an amino acid sequence of anyone of the VL CDR3s listed in Table 2 or Table 3.

In another embodiment, a composition of the present invention comprisesone or more antibodies or fragments thereof comprising one or more VHCDR3s having an amino acid sequence of any one of the VH CDR3s listed inTable 2 or Table 3 and one or more VL CDR1s having an amino acidsequence of any one of the VL CDR1s listed in Table 2 or Table 3. Inanother embodiment, a composition of the present invention comprises oneor more antibodies or fragments thereof comprising one or more VH CDR3shaving an amino acid sequence of any one of the VH CDR3s listed in Table2 or Table 3 and one or more VL CDR2s having an amino acid sequence ofany one of the VL CDR2s listed in Table 2 or Table 3. In a preferredembodiment, a composition of the present invention comprises one or moreantibodies or fragments thereof comprising one or more VH CDR3s havingan amino acid sequence of any one of the VH CDR3s listed in Table 2 orTable 3 and one or more VL CDR3s having an amino acid sequence of anyone of the VL CDR3s listed in Table 2 or Table 3. In yet anotherembodiment, a composition of the present invention comprises one or morefusion proteins, of the invention.

As discussed in more detail below, a composition of the invention may beused either alone or in combination with other compositions. Theantibodies or fragments thereof may further be recombinantly fused to aheterologous polypeptide at the N- or C-terminus or chemicallyconjugated (including covalently and non-covalently conjugations) topolypeptides or other compositions. For example, antibodies of thepresent invention may be recombinantly fused or conjugated to moleculesuseful as labels in detection assays and effector molecules such asheterologous polypeptides, drugs, radionuclides, or toxins. See, e.g.,PCT publications WO 92/08495; WO 91/14438; WO 89/12624; U.S. Pat. No.5,314,995; and EP 396,387.

Antibodies of the present invention or fragments thereof may be used,for example, to purify, detect, and target RSV antigens, in both invitro and in vivo diagnostic and therapeutic methods. For example, theantibodies or fragments have use in immunoassays for qualitatively andquantitatively measuring levels of the RSV in biological samples such assputum. See, e.g., Harlow et al., Antibodies: A Laboratory Manual, (ColdSpring Harbor Laboratory Press, 2nd ed. 1988) (incorporated by referenceherein in its entirety).

5.1.1. Antibody Conjugates

The present invention encompasses antibodies or fragments thereofrecombinantly fused or chemically conjugated (including both covalentlyand non-covalently conjugations) to a heterologous polypeptide (orportion thereof, preferably at least 10, at least 20, at least 30, atleast 40, at least 50, at least 60, at least 70, at least 80, at least90 or at least 100 amino acids of the polypeptide) to generate fusionproteins. The fusion does not necessarily need to be direct, but mayoccur through linker sequences. For example, antibodies may be used totarget heterologous polypeptides to particular cell types (e.g.,respiratory epithelial cells), either in vitro or in vivo, by fusing orconjugating the antibodies to antibodies specific for particular cellsurface receptors. Antibodies fused or conjugated to heterologouspolypeptides may also be used in in vitro immunoassays and purificationmethods using methods known in the art. See e.g., PCT publication WO93/21232; EP 439,095; Naramura et al., Immunol. Lett. 39:91-99 (1994);U.S. Pat. No. 5,474,981; Gillies et al., PNAS 89:1428-1432 (1992); andFell et al., J. Immunol. 146:2446-2452(1991), which are incorporated byreference in their entireties.

In one embodiment, a fusion protein of the invention comprises SYNAGIS®,AFFF, Pf12, P12f4, P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8C7,1X-493L1FR, H3-3F4, M3H9, Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10,A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, or A4B4-F52S and a heterologouspolypeptide. In another embodiment, a fusion protein of the inventioncomprises an antigen-binding fragment of SYNAGIS®, AFFF, Pf12, P12f4,P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8C7, 1X-493L1FR, H3-3F4, M3H9,Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1),A4B4L1FR-S28R, or A4B4-F52S and a heterologous polypeptide. In anotherembodiment, a fusion protein of the invention comprises one or more VHdomains having the amino acid sequence of any one of the VH domainslisted in Table 2 or one or more VL domains having the amino acidsequence of any one of the VL domains listed in Table 2 and aheterologous polypeptide. In another embodiment, a fusion protein of thepresent invention comprises one or more VH CDRs having the amino acidsequence of any one of the VH CDRs listed in Table 2 or Table 3 and aheterologous polypeptide. In another embodiment, a fusion proteincomprises one or more VL CDRs having the amino acid sequence of any oneof the VL CDRs listed in Table 2 or Table 3 and a heterologouspolypeptide. In another embodiment, a fusion protein of the inventioncomprises at least one VH domain and at least one VL domain listed inTable 2 and a heterologous polypeptide. In yet another embodiment, afusion protein of the invention comprises at least one VH CDR and atleast one VL CDR domain listed in Table 2 or Table 3 and a heterologouspolypeptide.

The present invention further includes compositions comprisingheterologous polypeptides fused or conjugated to antibody fragments. Forexample, the heterologous polypeptides may be fused or conjugated to aFab fragment, Fd fragment, Fv fragment, F(ab)₂ fragment, or portionthereof. Methods for fusing or conjugating polypeptides to antibodyportions are known in the art. See, e.g., U.S. Pat. Nos. 5,336,603,5,622,929, 5,359,046, 5,349,053, 5,447,851, and 5,112,946; EP 307,434;EP 367,166; PCT publication Nos. WO 96/04388 and WO 91/06570; Ashkenaziet al., Proc. NatI. Acad. Sci. USA 88: 10535-10539 (1991); Zheng et al.,J. Immunol. 154:5590-5600 (1995); and Vil et al., Proc. Natl. Acad. Sci.USA 89:11337-11341(1992) (said references incorporated by reference intheir entireties).

Additional fusion proteins of the invention may be generated through thetechniques of gene-shuffling, motif-shuffling, exon-shuffling, and/orcodon-shuffling (collectively referred to as “DNA shuffling”). DNAshuffling may be employed to alter the activities of antibodies of theinvention or fragments thereof (e.g., antibodies or fragments thereofwith higher affinities and lower dissociation rates). See, generally,U.S. Pat. Nos. 5,605,793; 5,811,238; 5,830,721; 5,834,252; and5,837,458, and Patten et al., Curr. Opinion Biotechnol. 8:724-33 (1997);Harayama, Trends Biotechnol. 16(2):76-82 (1998); Hansson, et al., J.Mol. Biol. 287:265-76 (1999); and Lorenzo and Blasco, Biotechniques24(2):308-13 (1998) (each of these patents and publications are herebyincorporated by reference in its entirety). In one embodiment,antibodies or fragments thereof, or the encoded antibodies or fragmentsthereof, may be altered by being subjected to random mutagenesis byerror-prone PCR, random nucleotide insertion or other methods prior torecombination. In another embodiment, one or more portions of apolynucleotide encoding an antibody or antibody fragment, which portionsimmunospecifically bind to a RSV antigen may be recombined with one ormore components, motifs, sections, parts, domains, fragments, etc. ofone or more heterologous molecules.

Moreover, the antibodies of the present invention or fragments thereofcan be fused to marker sequences, such as a peptide to facilitatepurification. In preferred embodiments, the marker amino acid sequenceis a hexa-histidine peptide, such as the tag provided in a pQE vector(QIAGEN, Inc., 9259 Eton Avenue, Chatsworth, Calif., 91311), amongothers, many of which are commercially available. As described in Gentzet al., 1989, Proc. Natl. Acad. Sci. USA 86:821-824, for instance,hexa-histidine provides for convenient purification of the fusionprotein. Other peptide tags useful for purification include, but are notlimited to, the hemagglutinin“HA” tag, which corresponds to an epitopederived from the influenza hemagglutinin protein (Wilson et al., 1984,Cell 37:767) and the “flag” tag.

The present invention further encompasses antibodies or fragmentsthereof conjugated to a diagnostic or therapeutic agent. The antibodiescan be used diagnostically to, for example, monitor the development orprogression of a RSV infection as part of a clinical testing procedureto, e.g., determine the efficacy of a given treatment regimen. Detectioncan be facilitated by coupling the antibody or fragment thereof to adetectable substance. Examples of detectable substances include variousenzymes, prosthetic groups, fluorescent materials, luminescentmaterials, bioluminescent materials, radioactive materials, positronemitting metals, and nonradioactive paramagnetic metal ions. Thedetectable substance may be coupled or conjugated either directly to theantibody (or fragment thereof) or indirectly, through an intermediate(such as, for example, a linker known in the art) using techniques knownin the art. See, for example, U.S. Pat. No. 4,741,900 for metal ionswhich can be conjugated to antibodies for use as diagnostics accordingto the present invention. Examples of suitable enzymes includehorseradish peroxidase, alkaline phosphatase, beta-galactosidase, oracetylcholinesterase; examples of suitable prosthetic group complexesinclude streptavidin/biotin and avidinjbiotin; examples of suitablefluorescent materials include umbelliferone, fluorescein, fluoresceinisothiocyanate, rhodamine, dichlorotriazinylamine fluorescein, dansylchloride or phycoerythrin; an example of a luminescent material includesluminol; examples of bioluminescent materials include luciferase,luciferin, and aequorin; and examples of suitable radioactive materialinclude ¹²⁵I, ¹³¹I, ¹¹¹In or ⁹⁹Tc.

An antibody or fragment thereof may be conjugated to a therapeuticmoiety such as a cytotoxin, e.g., a cytostatic or cytocidal agent, atherapeutic agent or a radioactive metal ion, e.g., alpha-emitters. Acytotoxin or cytotoxic agent includes any agent that is detrimental tocells. Examples include paclitaxol, cytochalasin B, gramicidin D,ethidium bromide, emetine, mitomycin, etoposide, tenoposide,vincristine, vinblastine, colchicin, doxorubicin, daunorubicin,dihydroxy anthracin dione, mitoxantrone, mithramycin, actinomycin D,1-dehydrotestosterone, glucocorticoids, procaine, tetracaine, lidocaine,propranolol, and puromycin and analogs or homologs thereof. Therapeuticagents include, but are not limited to, antimetabolites (e.g.,methotrexate, 6-mercaptopurine, 6-thioguanine, cytarabine,5-fluorouracil decarbazine), alkylating agents (e.g., mechlorethamine,thioepa chlorambucil, melphalan, carmustine (BSNU) and lomustine (CCNU),cyclothosphamide, busulfan, dibromomannitol, streptozotocin, mitomycinC, and cisdichlorodiamine platinum (II) (DDP) cisplatin), anthracyclines(e.g., daunorubicin (formerly daunomycin) and doxorubicin), antibiotics(e.g., dactinomycin (formerly actinomycin), bleomycin, mithramycin, andanthramycin (AMC)), and anti-mitotic agents (e.g., vincristine andvinblastine).

Further, an antibody or fragment thereof may be conjugated to atherapeutic agent or drug moiety that modifies a given biologicalresponse. Therapeutic agents or drug moieties are not to be construed aslimited to classical chemical therapeutic agents. For example, the drugmoiety may be a protein or polypeptide possessing a desired biologicalactivity. Such proteins may include, for example, a toxin such as abrin,ricin A, pseudomonas exotoxin, or diphtheria toxin; a protein such astumor necrosis factor, α-interferon, β-interferon, nerve growth factor,platelet derived growth factor, tissue plasminogen activator, anapoptotic agent, e.g., TNF-α, TNF-β, AIM I (see, InternationalPublication No. WO 97/33899), AIM II (see, International Publication No.WO 97/34911), Fas Ligand (Takahashi et al., 1994, J. Iminunol.,6:1567-1574), and VEGI (see, International Publication No. WO 99/23105),a thrombotic agent or an anti-angiogenic agent, e.g., angiostatin orendostatin; or, a biological response modifier such as, for example, alymphokine (e.g., interleukin-1 (“IL-1”), interleukin-2 (“IL-2”),interleukin-6 (“IL-6”), granulocyte macrophage colony stimulating factor(“GM-CSF”), and granulocyte colony stimulating factor (“G-CSF”)), or agrowth factor (e.g., growth hormone (“GH”)).

Techniques for conjugating such therapeutic moieties to antibodies arewell known, see, e.g., Arnon et al., “Monoclonal Antibodies ForImmunotargeting Of Drugs In Cancer Therapy”, in Monoclonal AntibodiesAnd Cancer Therapy, Reisfeld et al. (eds.), pp. 243-56 (Alan R. Liss,Inc. 1985); Hellstrom et al., “Antibodies For Drug Delivery”, inControlled Drug Delivery (2nd Ed.), Robinson et al. (eds.), pp. 623-53(Marcel Dekker, Inc. 1987); Thorpe, “Antibody Carriers Of CytotoxicAgents In Cancer Therapy: A Review”, in Monoclonal Antibodies '84:Biological And Clinical Applications, Pinchera et al. (eds.), pp.475-506 (1985); “Analysis, Results, And Future Prospective Of TheTherapeutic Use Of Radiolabeled Antibody In Cancer Therapy”, inMonoclonal Antibodies For Cancer Detection And Therapy, Baldwin et al.(eds.), pp. 303-16 (Academic Press 1985), and Thorpe et al., 1982,Immunol. Rev. 62:119-58.

An antibody or fragment thereof, with or without a therapeutic moietyconjugated to it, administered alone or in combination with cytotoxicfactor(s) and/or cytokine(s) can be used as a therapeutic.

Alternatively, an antibody can be conjugated to a second antibody toform an antibody heteroconjugate as described by Segal in U.S. Pat. No.4,676,980, which is incorporated herein by reference in its entirety.

Antibodies may also be attached to solid supports, which areparticularly useful for immunoassays or purification of the targetantigen. Such solid supports include, but are not limited to, glass,cellulose, polyacrylamide, nylon, polystyrene, polyvinyl chloride orpolypropylene.

5.2. Prophylactic and Therapeutic Uses of Antibodies

The present invention is directed to antibody-based therapies whichinvolve administering antibodies of the invention or fragments thereofto a mammal, preferably a human, for preventing, treating, orameliorating one or more symptoms associated with a RSV infection.Prophylactic and therapeutic compounds of the invention include, but arenot limited to, antibodies of the invention (including fragments,analogs and derivatives thereof as described herein) and nucleic acidsencoding antibodies of the invention (including fragments, analogs andderivatives thereof and anti-idiotypic antibodies as described herein).Antibodies of the invention, or fragments thereof may be provided inpharmaceutically acceptable compositions as known in the art or asdescribed herein.

Antibodies of the present invention or fragments thereof that functionas antagonists of a RSV infection can be administered to a mammal,preferably a human, to treat, prevent or ameliorate one or more symptomsassociated with a RSV infection. For example, antibodies or fragmentsthereof which disrupt or prevent the interaction between a RSV antigenand its host cell receptor may be administered to a mammal, preferably ahuman, to treat, prevent or ameliorate one or more symptoms associatedwith a RSV infection.

In a specific embodiment, an antibody or fragment thereof prevents RSVfrom binding to its host cell receptor by at least 99%, at least 95%, atleast 90%, at least 85%, at least 80%, at least 75%, at least 70%, atleast 60%, at least 50%, at least 45%, at least 40%, at least 45%, atleast 35%, at least 30%, at least 25%, at least 20%, or at least 10%relative to RSV binding to its host cell receptor in the absence of saidantibodies or antibody fragments. In another embodiment, a combinationof antibodies, a combination of antibody fragments, or a combination ofantibodies and antibody fragments prevent RSV from binding to its hostcell receptor by at least 99%, at least 95%, at least 90%, at least 85%,at least 80%, at least 75%, at least 70%, at least 60%, at least 50%, atleast 45%, at least 40%, at least 45%, at least 35%, at least 30%, atleast 25%, at least 20%, or at least 10% relative to RSV binding to itshost cell receptor in the absence of said antibodies and/or antibodyfragments.

Antibodies or fragments thereof which do not prevent RSV from bindingits host cell receptor but inhibit or downregulate RSV replication canalso be administered to a mammal to treat, prevent or ameliorate one ormore symptoms associated with a RSV infection. The ability of anantibody or fragment thereof to inhibit or downregulate RSV replicationmay be determined by techniques described herein or otherwise known inthe art. For example, the inhibition or downregulation of RSVreplication can be determined by detecting the RSV titer in the lungs ofa mammal, preferably a human.

In a specific embodiment, an antibody of the present invention orfragment thereof inhibits or downregulates RSV replication by at least99%, at least 95%, at least 90%, at least 85%, at least 80%, at least75%, at least 70%, at least 60%, at least 50%, at least 45%, at least40%, at least 45%, at least 35%, at least 30%, at least 25%, at least20%, or at least 10% relative to RSV replication in absence of saidantibodies or antibody fragments. In another embodiment, a combinationof antibodies, a combination of antibody fragments, or a combination ofantibodies and antibody fragments inhibit or downregulate RSVreplication by at least 99%, at least 95%, at least 90%, at least 85%,at least 80%, at least 75%, at least 70%, at least 60%, at least 50%, atleast 45%, at least 40%, at least 45%, at least 35%, at least 30%, atleast 25%, at least 20%, or at least 10% relative to RSV replication inabsence of said antibodies and/or antibody fragments.

One or more antibodies of the present invention or fragments thereofthat immunospecifically bind to one or more RSV antigens may be usedlocally or systemically in the body as a therapeutic. The antibodies ofthis invention or fragments thereof may also be advantageously utilizedin combination with other monoclonal or chimeric antibodies, or withlymphokines or hematopoietic growth factors (such as, e.g., IL-2, IL-3and IL-7), which, for example, serve to increase the number or activityof effector cells which interact with the antibodies. The antibodies ofthis invention or fragments thereof may also be advantageously utilizedin combination with other monoclonal or chimeric antibodies, or withlymphokines or hematopoietic growth factors (such as, e.g., IL-2, IL-3and IL-7), which, for example, serve to increase the immune response.The antibodies of this invention or fragments thereof may also beadvantageously utilized in combination with one or more drugs used totreat RSV infection such as, for example anti-viral agents. Antibodiesof the invention or fragments may be used in combination with one ormore of the following drugs: NIH-351 (Gemini Technologies), recombinantRSV vaccine (Aviron), RSVf-2 (Intracel), F-50042 (Pierre Fabre), T-786(Trimeris), VP-36676 (ViroPharma), RFI-641 (American Home Products),VP-14637 (ViroPharma), PFP-1 and PFP-2 (American Home Products), RSVvaccine (Avant Immunotherapeutics), and F-50077 (Pierre Fabre).

The antibodies of the invention may be administered alone or incombination with other types of treatments (e.g., hormonal therapy,immunotherapy, and anti-inflammatory agents). Generally, administrationof products of a species origin or species reactivity (in the case ofantibodies) that is the same species as that of the patient ispreferred. Thus, in a preferred embodiment, human or humanizedantibodies, fragments derivatives, analogs, or nucleic acids, areadministered to a human patient for therapy or prophylaxis.

It is preferred to use high affinity and/or potent in vivo inhibitingantibodies and/or neutralizing antibodies that immunospecifically bindto a RSV antigen, for both immunoassays directed to RSV, prevention ofRSV infection and therapy for RSV infection. It is also preferred to usepolynucleotides encoding high affinity and/or potent in vivo inhibitingantibodies and/or neutralizing antibodies that immunospecifically bindto a RSV antigen, for both immunoassays directed to RSV and therapy forRSV infection. Such antibodies or fragments thereof will preferably havean affinity for the RSV F glycoprotein and/or fragments of the Fglycoprotein.

In one embodiment, therapeutic or pharmaceutical compositions comprisingantibodies of the invention or fragments thereof are administered to amammal, preferably a human, to treat, prevent or ameliorate one or moresymptoms associated with RSV infection. In another embodiment,therapeutic or pharmaceutical compositions comprising antibodies of theinvention or fragments thereof are administered to a human with cysticfibrosis, bronchopulmonary dysplasia, congenital heart disease,congenital immunodeficiency or acquired immunodeficiency, or to a humanwho has had a bone marrow transplant to treat, prevent or ameliorate oneor more symptoms associated with RSV infection. In another embodiment,therapeutic or pharmaceutical compositions comprising antibodies of theinvention or fragments thereof are administered to a human infant,preferably a human infant born prematurely or a human infant at risk ofhospitalization for RSV infection to treat, prevent or ameliorate one ormore symptoms associated with RSV infection. In yet another embodiment,therapeutic or pharmaceutical compositions comprising antibodies of theinvention or fragments thereof are administered to the elderly or peoplein group homes (e.g., nursing homes or rehabilitation centers).

In a specific embodiment, a mammal, preferably a human, is administereda therapeutic or pharmaceutical composition comprising one or moreantibodies of the present invention or fragments thereof for thetreatment, prevention or amelioration of one or more symptoms associatedwith a RSV infection in an amount effective for decreasing RSV titers.In accordance with this embodiment, an effective amount of antibodies orantibody fragments reduces the RSV titers in the lung as measured, forexample, by the concentration of RSV in sputum samples or a lavage fromthe lungs from a mammal. In another embodiment, a mammal, preferably ahuman, is administered a therapeutic or pharmaceutical compositioncomprising one or more antibodies of the present invention or fragmentsthereof for the treatment, prevention or amelioration of symptomsassociated with a RSV infection in an amount effective for inducing animmune response in the mammal.

In another embodiment, a mammal, preferably a human, is administered afirst dose of a therapeutic or pharmaceutical composition comprisingless than 15 mg/kg, preferably less than 10 mg/kg, less than 5 mg/kg,less than 3 mg/kg, less than 1 mg/kg or less than 0.5 mg/kg of one ormore antibodies or fragments thereof that immunospecifically bind to oneor more RSV antigens with higher affinity and/or higher avidity thanpreviously known antibodies (e.g., SYNAGIS®) for the prevention,treatment or amelioration of one or more symptoms associated with a RSVinfection in an amount effective to induce a serum titer of at least 1μg/ml, preferably at least 2 μg/ml, at least 5 μg/ml, at least 10 μg/ml,at least 15 μg/ml, at least 20 μg/ml, or at least 25 μg/ml 20 days(preferably 25, 30, 35, 40 days) after the administration of the firstdose and prior to the administration of a subsequent dose. Preferably,the serum titer of said antibodies or antibody fragments is less than 30μg/ml 30 days after the administration of the first dose and prior tothe administration of a subsequent dose. Preferably, said antibodies areAFFF, Pf12, P12f4, P11fd4, A1e9, A12a6, A13c4, A17d4, A4B4, A8C7,1X-493L1FR, H3-3F4, M3H9, Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10,A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, and A4B4-F52S

In another embodiment, a mammal, preferably a human, is administered afirst dose of a therapeutic or pharmaceutical composition comprisingless than 15 mg/kg, preferably less than 5 mg/kg, less than 3 mg/kg,less than 1 mg/kg or less than 0.5 mg/kg of one or more antibodies orfragments thereof which have increased in vivo half-lives and whichimmunospecifically bind to one or more RSV antigens with higher affinityand/or higher avidity than previously known antibodies (e.g., SYNAGIS®)for the prevention, treatment or amelioration of one or more symptomsassociated with a RSV infection in an amount effective to induce a serumtiter of at least 1 μg/ml, preferably at least 2 μg/ml, at least 5μg/ml, at least 10 μg/ml, at least 15 μg/ml, at least 20 μg/ml, or atleast 25 μg/ml 25 days (preferably 30, 35, or 40 days) after theadministration of the first dose and prior to the administration of asubsequent dose. Preferably, the serum titer of said antibodies orantibody fragments is less than 30 μg/ml 30 days after theadministration of the first dose and prior to the administration of asubsequent dose. Preferably, the novel antibodies are AFFF, Pf12, P12f4,P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8C7, 1X-493L1FR, H3-3F4, M3H9,Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1),A4B4L1FR-S28R, and A4B4-F52S.

In another embodiment, a mammal, preferably a human, is administered afirst dose of a therapeutic or pharmaceutical composition comprisingapproximately 15 mg/kg of HL-SYNAGIS or antigen-binding fragmentsthereof for the prevention, treatment or amelioration of one or moresymptoms associated with a RSV infection in an amount effective toinduce a serum titer of at least 1 μg/ml, preferably at least 30 μg/ml,at least 35 μg/ml, at least 40 μg/ml, or at least 50 μg/ml 25 days(preferably 30, 35, or 40 days) after the administration of the firstdose and prior to the administration of a subsequent dose. In anotherembodiment, a mammal, preferably a human, is administered a first doseof a therapeutic or pharmaceutical composition comprising less than 15mg/kg (preferably 10 mg/kg or less, 5 mg/kg or less, 3 mg/kg or less, 1mg/kg or less, or 0.5 mg/kg or less) of HL-SYNAGIS or antigen-bindingfragments thereof for the prevention, treatment or amelioration of oneor more symptoms associated with a RSV infection in an amount effectiveto induce a serum titer of at least 1 μg/ml, preferably at least 30μg/ml, at least 35 μg/ml, at least 40 μg/ml, or at least 50 μg/ml 25days (preferably 30, 35, or 40 days) after the administration of thefirst dose and prior to the administration of a subsequent dose.

The present invention encompasses therapeutic or pharmaceuticalcompositions for pulmonary delivery comprising one or more antibodies orfragments thereof which immunospecifically bind to one or more RSVantigens with a higher affinity and/or a higher avidity than previouslyknown antibodies (e.g., SYNAGIS®). The present invention alsoencompasses therapeutic or pharmaceutical compositions for pulmonarydelivery comprising SYNAGIS® or an antigen-binding fragment thereof.

In one embodiment, a mammal, preferably a human, is administered a firstdose of a therapeutic or pharmaceutical composition for pulmonarydelivery comprising less than 15 mg/kg, preferably less than 5 mg/kg,less than 3 mg/kg, less than 1 mg/kg or less than 0.5 mg/kg, or lessthan 0.01 mg/kg of one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens with higher affinityand/or higher avidity than previously known antibodies (e.g., SYNAGIS®)for the prevention, treatment or amelioration of one or more symptomsassociated with a RSV infection in an amount effective to induce a titerof 20 ng per mg of lung protein (preferably at least 40 ng/mg, at least60 ng/mg, at least 80 ng/mg, at least 50 ng/mg, at least 75 ng/mg, atleast 100 ng/mg, or at least 150 ng/mg) in an intubation sample orlavage from the lungs of said mammal 20 days (preferably 25, 30, 35, or40 days) after the administration of the first dose and prior to theadministration of a subsequent dose. Preferably, the serum titer of saidantibodies or antibody fragments is less than 100 ng/ml of protein 30days after the administration of the first dose and prior to theadministration of a subsequent dose. Preferably, the novel antibodiesare AFFF, Pf12, P12f4, P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8C7,1X-493L1FR, H3-3F4, M3H9, Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10,A13a11, A1h5, A4B4(1), A4B4L1FR-S28R, and A4B4-F52S.

In another embodiment, a mammal, preferably a human, is administered afirst dose of a therapeutic or pharmaceutical composition for pulmonarydelivery comprising approximately 15 mg/kg of SYNAGIS® or fragmentsthereof for the prevention, treatment or amelioration of one or moresymptoms associated with a RSV infection in an amount effective toinduce a titer of 20 ng per mg of lung protein (preferably at least 40ng/mg, at least 60 ng/mg, at least 80 ng/mg, at least 50 ng/mg, at least75 ng/mg, at least 100 ng/mg, or at least 150 ng/mg) an intubationsample or lavage from the lungs of said mammal 30 days (preferably 35 or40 days) after the administration of the first dose and prior to theadministration of a subsequent dose. In another embodiment, a mammal,preferably a human, is administered a first dose of a therapeutic orpharmaceutical composition for pulmonary delivery comprising less than15 mg/kg (preferably 10 mg/kg or less, 5 mg/kg or less, 3 mg/kg or less,1 mg/kg or less, or 0.5 mg/kg or less) of SYNAGIS® or fragments thereoffor the prevention of a RSV infection in an amount effective to induce atiter of 20 ng per mg of lung protein (preferably at least 40 ng/mg, atleast 60 ng/mg, at least 80 ng/mg, at least 50 ng/mg, at least 75 ng/mg,at least 100 ng/mg, or at least 150 ng/mg) in an intubation sample orlavage from the lungs of said mammal 30 days (preferably 35 or 40 days)after the administration of the first dose and prior to theadministration of a subsequent dose.

The present invention encompasses therapeutic or pharmaceuticalcompositions for pulmonary delivery comprising one or more antibodies orfragments thereof which have increased in vivo half-lives and whichimmunospecifically bind to one or more RSV antigens with a higheraffinity and/or a higher avidity than previously known antibodies (e.g.,SYNAGIS®). The present invention also encompasses therapeutic orpharmaceutical compositions for pulmonary delivery comprising HL-SYNAGISor an antigen-binding fragment thereof.

The present invention encompasses sustained release compositionscomprising one or more antibodies or fragments thereof which haveincreased in vivo half-lives and which immunospecifically bind to one ormore RSV antigens with a higher affinity and/or a higher avidity thanpreviously known antibodies (e.g., SYNAGIS®). The present invention alsoencompasses sustained release compositions comprising SYNAGIS® or anantigen-binding fragment thereof.

In one embodiment, a mammal, preferably a human, is administered a firstdose of a sustained release formulation comprising less than 15 mg/kg,preferably less than 5 mg/kg, less than 3 mg/kg, less than 1 mg/kg orless than 0.5 mg/kg of one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens with higher affinityand/or higher avidity than previously known antibodies (e.g, SYNAGIS®)for the prevention, treatment or amelioration of one or more symptomsassociated with a RSV infection in an amount effective to induce a serumtiter of at least 1 μg/ml, preferably at least 2 μg/ml, at least 5μg/ml, at least 10 μg/ml, at least 15 μg/ml, at least 20 μg/ml, or atleast 25 μg/ml for at least 10 days (preferably at least 15, at least20, at least 25, at least 30, at least 35, or at least 40 days) afterthe administration of the first dose and prior to the administration ofa subsequent dose. Preferably, the serum titer of said antibodies orantibody fragments is less than 30 μg/ml 30 days after theadministration of the first dose and prior to the administration of asubsequent dose. Preferably, the novel antibodies are AFFF, Pf12, P12f4,P11d4, A1e9, A12a6, A13c4, A17d4, A4B4, A8C7, 1X-493L1FR, H3-3F4, M3H9,Y10H6, DG, AFFF(1), 6H8, L1-7E5, L2-15B10, A13a11, A1h5, A4B4(1),A4B4L1FR-S28R, or A4B4-F52S.

In another embodiment, a mammal, preferably a human, is administered afirst dose of a sustained release formulation comprising less than 15mg/kg, preferably less than 5 mg/kg, less than 3 mg/kg, less than 1mg/kg or less than 0.5 mg/kg of one or more antibodies or fragmentsthereof which immunospecifically bind to one or more RSV antigens withhigher affinity and/or higher avidity than previously known antibodies(e.g., SYNAGIS®) for the prevention, treatment, or amelioration of oneor more symptoms associated with a RSV infection in an amount effectiveto induce a serum titer of 1 μg/ml, preferably 2 μg/ml, 5 μg/ml, 10μg/ml, 15 μg/ml, 20 μg/ml, or 25 μg/ml that is maintained for at least10 days (preferably at least 15, at least 20, at least 25, at least 30,at least 35, or at least 40 days) after the administration of the firstdose and prior to the administration of a subsequent dose withoutexceeding a serum titer of 30 μg/ml.

In another embodiment, a mammal, preferably a human, is administered afirst dose of a sustained release formulation comprising approximately15 mg/kg of SYNAGIS® or fragments thereof for the prevention, treatmentor amelioration of one or more symptoms associated with a RSV infectionin an amount effective to induce a titer of at least 30 μg/ml,preferably at least 35 μg/ml, at least 40 μg/ml, or at least 50 μg/ml 25days (preferably 30, 35, or 40 days) after the administration of thefirst dose and prior to the administration of a subsequent dose. Inanother embodiment, a mammal, preferably a human, is administered afirst dose of a sustained release formulation comprising less than 15mg/kg (preferably 10 mg/kg or less, 5 mg/kg or less, 3 mg/kg or less, 1mg/kg or less, or 0.5 mg/kg or less) of SYNAGIS® or fragments thereoffor the prevention of a RSV infection in an amount effective to induceat least 30 μg/ml, preferably at least 35 μg/ml, at least 40 μg/ml, orat least 50 μg/ml 25 days (preferably 30, 35, or 40 days) after theadministration of the first dose and prior to the administration of asubsequent dose.

In another embodiment, a mammal, preferably a human, is administered afirst dose of a sustained release formulation comprising less than 15mg/kg, preferably less than 5 mg/kg, less than 3 mg/kg, less than 1mg/kg or less than 0.5 mg/kg of SYNAGISS or an antigen-binding fragmentthereof for the prevention, treatment, or amelioration of one or moresymptoms associated with a RSV infection in an amount effective toinduce a serum titer of 1 μg/ml, preferably 2 μg/ml, 5 μg/ml, 10 μg/ml,15 μg/ml, 20 μg/ml, or 25 μg/ml that is maintained for at least 10 days(preferably at least 15, at least 20, at least 25, at least 30, at least35, or at least 40 days) after the administration of the first dose andprior to the administration of a subsequent dose without exceeding aserum titer of 30 μg/ml.

The present invention encompasses sustained release formulationscomprising one or more antibodies or fragments thereof which haveincreased in vivo half-lives and which immunospecifically bind to one ormore RSV antigens with a higher affinity and/or a higher avidity thanpreviously known antibodies such as, e.g., SYNAGIS(V. The presentinvention also encompasses sustained release formulations comprisingHL-SYNAGIS or an antigen-binding fragment thereof.

The present invention encompasses sustained release formulations forpulmonary delivery comprising one or more antibodies or fragmentsthereof which immunospecifically bind to one or more RSV antigens with ahigher affinity and/or a higher avidity than previously known antibodies(e.g., SYNAGIS®). The present invention also encompasses sustainedrelease formulations for pulmonary delivery comprising one or moreantibodies or fragments thereof which have increased in vivo half-livesand which immunospecifically bind to one or more RSV antigens with ahigher affinity and/or a higher avidity than previously known antibodies(e.g., SYNAGIS®). The present invention also encompasses sustainedrelease formulations for pulmonary delivery comprising SYNAGIS® orfragments thereof. The present invention further encompasses sustainedrelease formulations for pulmonary delivery comprising HL-SYNAGIS or anantigen-binding fragment thereof.

In another embodiment, a mammal, preferably a human, is administered afirst dose of a therapeutic or pharmaceutical composition comprisingless than 10 mg/kg, less than 5 mg/kg, less than 3 mg/kg, less than 1mg/kg or less than 0.5 mg/kg of one or more antibodies of the presentinvention or fragments thereof for the prevention, treatment oramelioration of one or more symptoms associated with a RSV infection inan amount effective to induce a serum titer of at least 35 μg/ml, atleast 40 μg/ml, at least 50 μg/ml, at least 80 μg/ml, at least 100 1g/ml, at least 120 μg/ml, at least 150 1 g/ml, at least 200 μg/ml, atleast 250 μg/ml, or at least 300 μg/ml 20 days (preferably 25, 30, 35 or40 days) after the administration of the first dose. In anotherembodiment, a mammal, preferably a human, is administered a first doseof a therapeutic or pharmaceutical composition comprising approximately15 mg/kg of one or more antibodies of the present invention or fragmentsthereof for the prevention, treatment or amelioration of one or moresymptoms associated with a RSV infection in an amount effective toinduce a serum titer of at least 100 μg/ml, at least 125 μg/ml, at least150 μg/ml, at least 200 μg/ml, at least 250 μg/ml, at least 300 μg/ml,at least 350 μg/ml, at least 400 μg/ml, or at least 450 μg/ml 20 days(preferably 25, 30, 35 or 40 days) after the administration of the firstdose. The term “approximately 15 mg/kg” as used herein refers to a rangeof between 14 mg/kg and 16 mg/kg.

In another embodiment, a mammal, preferably a human, is administered adose of a pharmaceutical composition comprising one or more antibodiesof the present invention or fragments thereof for the prevention a RSVinfection in an amount effective to induce a prophylactically effectiveserum titer of less than 10 μg/ml, less than 8 μg/ml, less than 5 μg/ml,less than 3 μg/ml, less than 1 μg/ml, or less than 0.5 μg/ml 30 daysafter the administration of the dose, wherein said prophylacticallyeffective serum titer is the serum titer that reduces the incidence ofRSV infection in the human or the serum titer in a cotton rat thatresults in a RSV titer 5 days after challenge with 10⁵ pfu RSV that is99% lower than the RSV titer in the cotton rat 5 days after challengewith 10⁵ pfu of RSV in a cotton rat not administered the dose prior tochallenge. Preferably, the dose of the pharmaceutical compositioncomprises less than 10 mg/kg, less than 5 mg/kg, less than 3 mg/kg, lessthan 1 mg/kg, or less than 0.5 mg/kg of one or more antibodies of thepresent invention or fragments thereof.

In yet another embodiment, a mammal, preferably a human, is administereda dose of a therapeutic or pharmaceutical composition comprising one ormore antibodies of the present invention or fragments thereof for thetreatment or amelioration of one or more symptoms associated with a RSVinfection in an amount effective to induce a therapeutically effectiveserum titer of less than 10 μg/ml, less than 8 μg/ml, less than 5 μg/ml,less than 3 μg/ml, less than 1 μg/ml, or less than 0.5 μg/ml 30 daysafter the administration of the dose, wherein said therapeuticallyeffective serum titer is the serum titer that reduces the severity orlength of RSV infection or is the serum titer in a cotton rat thatresults in a RSV titer in the rat 5 days after challenge with 10⁵ pfuRSV that is 99% lower than the RSV titer 5 days after challenge with 10⁵pfu of RSV in a cotton rat not administered the dose prior to challenge.Preferably, the dose of the therapeutic or pharmaceutical compositioncomprises less than 12 mg/kg, less than 10 mg/kg, less than 5 mg/kg,less than 3 mg/kg, less than 1 mg/kg, or less than 0.5 mg/kg of one ormore antibodies of the present invention or fragments thereof.

5.3. Methods of Administration of Antibodies

The invention provides methods of treatment, prophylaxis, andamelioration of one or more symptoms associated with RSV infection byadministrating to a subject of an effective amount of antibody orfragment thereof, or pharmaceutical composition comprising an antibodyof the invention or fragment thereof. In a preferred aspect, an antibodyor fragment thereof is substantially purified (i.e., substantially freefrom substances that limit its effect or produce undesiredside-effects). The subject is preferably a mammal such as non-primate(e.g., cows, pigs, horses, cats, dogs, rats etc.) and a primate (e.g.,monkey such as a cynomolgous monkey and a human). In a preferredembodiment, the subject is a human. In another preferred embodiment, thesubject is a human infant or a human infant born prematurely. In anotherembodiment, the subject is a human with cystic fibrosis,bronchopulmonary dysplasia, congenital heart disease, congenitalimmunodeficiency or acquired immunodeficiency, a human who has had abone marrow transplant, or an elderly human

Various delivery systems are known and can be used to administer anantibody of the invention or a fragment thereof, e.g., encapsulation inliposomes, microparticles, microcapsules, recombinant cells capable ofexpressing the antibody or antibody fragment, receptor-mediatedendocytosis (see, e.g., Wu and Wu, J. Biol. Chem. 262:4429-4432 (1987)),construction of a nucleic acid as part of a retroviral or other vector,etc. Methods of administering an antibody or fragment thereof, orpharmaceutical composition include, but are not limited to, parenteraladministration (e.g., intradermal, intramuscular, intraperitoneal,intravenous and subcutaneous), epidural, and mucosal (e.g., intranasaland oral routes). In a specific embodiment, antibodies of the presentinvention or fragments thereof, or pharmaceutical compositions areadministered intramuscularly, intravenously, or subcutaneously. Thecompositions may be administered by any convenient route, for example byinfusion or bolus injection, by absorption through epithelial ormucocutaneous linings (e.g., oral mucosa, rectal and intestinal mucosa,etc.) and may be administered together with other biologically activeagents. Administration can be systemic or local. In addition, pulmonaryadministration can also be employed, e.g., by use of an inhaler ornebulizer, and formulation with an aerosolizing agent. See, e.g., U.S.Pat. Nos. 6,019,968, 5,985, 320, 5,985,309, 5,934,272, 5,874,064,5,855,913, 5,290,540, and 4,880,078; and PCT Publication Nos. WO92/19244, WO 97/32572, WO 97/44013, WO 98/31346, and WO 99/66903, eachof which is incorporated herein by reference their entirety. In apreferred embodiment, an antibody of the invention or fragment thereof,or composition of the invention is administered using Alkermes AIR™pulmonary drug delivery technology (Alkermes, Inc., Cambridge, Mass.).

The invention provides for any method of administrating lower doses ofknown antibodies or fragments thereof which immunospecifically bind toone or more RSV antigens than previously thought to be effective for theprevention, treatment or amelioration of one or more symptoms associatedwith a RSV infection. Preferably, lower doses of known antibodies orfragments thereof which immunospecifically bind to one or more RSVantigens are administered by pulmonary administration. The presentinvention also provides for any method of administering a novel antibodyof the invention or fragment thereof for the prevention, treatment oramelioration of one or more symptoms associated with a RSV infection.Preferably, novel antibodies of the invention or fragments thereof areadministered by pulmonary administration.

The invention also provides that an antibody or fragment thereof ispackaged in a hermetically sealed container such as an ampoule orsachette indicating the quantity of antibody or antibody fragment. Inone embodiment, the antibody or antibody fragment is supplied as a drysterilized lyophilized powder or water free concentrate in ahermetically sealed container and can be reconstituted, e.g., with wateror saline to the appropriate concentration for administration to asubject. Preferably, the antibody or antibody fragment is supplied as adry sterile lyophilized powder in a hermetically sealed container at aunit dosage of at least 5 mg, more preferably at least 10 mg, at least15 mg, at least 25 mg, at least 35 mg, at least 45 mg, at least 50 mg,or at least 75 mg. The lyophilized antibody or antibody fragment shouldbe stored at between 2 and 8° C. in its original container and theantibody or antibody fragment should be administered within 12 hours,preferably within 6 hours, within 5 hours, within 3 hours, or within 1hour after being reconstituted. In an alternative embodiment, anantibody or fragment thereof is supplied in liquid form in ahermetically sealed container indicating the quantity and concentrationof the antibody or antibody fragment. Preferably, the liquid form of theantibody or fragment thereof is supplied in a hermetically sealedcontainer at least 1 mg/ml, more preferably at least 2.5 mg/ml, at least5 mg/ml, at least 8 mg/ml, at least 10 mg/ml, at least 15 mg/kg, or atleast 25 mg/ml.

In a specific embodiment, it may be desirable to administer thepharmaceutical compositions of the invention locally to the area in needof treatment; this may be achieved by, for example, and not by way oflimitation, local infusion, by injection, or by means of an implant,said implant being of a porous, non-porous, or gelatinous material,including membranes, such as sialastic membranes, or fibers. Preferably,when administering a an antibody of the invention or fragment thereof,care must be taken to use materials to which the antibody or antibodyfragment does not absorb.

In another embodiment, the composition can be delivered in a vesicle, inparticular a liposome (see Langer, Science 249:1527-1533 (1990); Treatet al., in Liposomes in the Therapy of Infectious Disease and Cancer,Lopez-Berestein and Fidler (eds.), Liss, New York, pp. 353-365 (1989);Lopez-Berestein, ibid., pp. 3 17-327; see generally ibid.).

In yet another embodiment, the composition can be delivered in acontrolled release or sustained release system. In one embodiment, apump may be used to achieve controlled or sustained release (see Langer,supra; Sefton, 1987, CRC Crit. Ref. Biomed. Eng. 14:20; Buchwald et al.,1980, Surgery 88:507; Saudek et al., 1989, N. Engl. J. Med. 321:574). Inanother embodiment, polymeric materials can be used to achievecontrolled or sustained release of the antibodies of the invention orfragments thereof (see e.g., Medical Applications of Controlled Release,Langer and Wise (eds.), CRC Pres., Boca Raton, Fla. (1974); ControlledDrug Bioavailability, Drug Product Design and Performance, Smolen andBall (eds.), Wiley, New York (1984); Ranger and Peppas, 1983, J.,Macromol. Sci. Rev. Macromol. Chem. 23:61; see also Levy et al., 1985,Science 228:190; During et al., 1989, Ann. Neurol. 25:351; Howard etal., 1989, J. Neurosurg. 7 1:105); U.S. Pat. No. 5,679,377; U.S. Pat.No. 5,916,597; U.S. Pat. No. 5,912,015; U.S. Pat. No. 5,989,463; U.S.Pat. No. 5,128,326; PCT Publication No. WO 99/15154; and PCT PublicationNo. WO 99/20253. Examples of polymers used in sustained releaseformulations include, but are not limited to, poly(2-hydroxy ethylmethacrylate), poly(methyl methacrylate), poly(acrylic acid),poly(ethylene-co-vinyl acetate), poly(methacrylic acid), polyglycolides(PLG), polyanhydrides, poly(N-vinyl pyrrolidone), poly(vinyl alcohol),polyacrylamide, poly(ethylene glycol), polylactides (PLA),poly(lactide-co-glycolides) (PLGA), and polyorthoesters. In a preferredembodiment, the polymer used in a sustained release formulation isinert, free of leachable impurities, stable on storage, sterile, andbiodegradable. In yet another embodiment, a controlled or sustainedrelease system can be placed in proximity of the therapeutic target,i.e., the lungs, thus requiring only a fraction of the systemic dose(see, e.g., Goodson, in Medical Applications of Controlled Release,supra, vol. 2, pp. 115-138 (1984)).

Controlled release systems are discussed in the review by Langer (1990,Science 249:1527-1533). Any technique known to one of skill in the artcan be used to produce sustained release formulations comprising one ormore antibodies of the invention or fragments thereof. See, e.g., U.S.Pat. No. 4,526,938, PCT publication WO 91/05548, PCT publication WO96/20698,.Ning et al., 1996, “Intratumoral Radioimmunotheraphy of aHuman Colon Cancer Xenograft Using a Sustained-Release Gel,”Radiotherapy & Oncology 39:179-189,.Song et al., 1995, “AntibodyMediated Lung Targeting of Long-Circulating Emulsions,” PDA Journal ofPharmaceutical Science & Technology 50:372-397, Cleek et al., 1997,“Biodegradable Polymeric Carriers for a bFGF Antibody for CardiovascularApplication,” Pro. Int'l. Symp. Control. Rel. Bioact. Mater. 24:853-854,and Lam et al., 1997, “Microencapsulation of Recombinant HumanizedMonoclonal Antibody for Local Delivery,” Proc. Int'l. Symp. Control Rel.Bioact. Mater. 24:759-760, each of which is incorporated herein byreference in their entirety.

In a specific embodiment where the composition of the invention is anucleic acid encoding an antibody or antibody fragment, the nucleic acidcan be administered in vivo to promote expression of its encodedantibody or antibody fragment, by constructing it as part of anappropriate nucleic acid expression vector and administering it so thatit becomes intracellular, e.g., by use of a retroviral vector (see U.S.Pat. No. 4,980,286), or by direct injection, or by use of microparticlebombardment (e.g., a gene gun; Biolistic, Dupont), or coating withlipids or cell-surface receptors or transfecting agents, or byadministering it in linkage to a homeobox-like peptide which is known toenter the nucleus (see e.g., Joliot et al., 1991, Proc. Natl. Acad. Sci.USA 88:1864-1868), etc. Alternatively, a nucleic acid can be introducedintracellularly and incorporated within host cell DNA for expression byhomologous recombination.

The present invention also provides pharmaceutical compositions. Suchcompositions comprise a prophylactically or therapeutically effectiveamount of an antibody or a fragment thereof, and a pharmaceuticallyacceptable carrier. In a specific embodiment, the term “pharmaceuticallyacceptable” means approved by a regulatory agency of the Federal or astate government or listed in the U.S. Pharmacopeia or other generallyrecognized pharmacopeia for use in animals, and more particularly inhumans. The term “carrier” refers to a diluent, adjuvant (e.g., Freund'sadjuvant (complete and incomplete)), excipient, or vehicle with whichthe therapeutic is administered. Such pharmaceutical carriers can besterile liquids, such as water and oils, including those of petroleum,animal, vegetable or synthetic origin, such as peanut oil, soybean oil,mineral oil, sesame oil and the like. Water is a preferred carrier whenthe pharmaceutical composition is administered intravenously. Salinesolutions and aqueous dextrose and glycerol solutions can also beemployed as liquid carriers, particularly for injectable solutions.Suitable pharmaceutical excipients include starch, glucose, lactose,sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate,glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol,propylene, glycol, water, ethanol and the like. The composition, ifdesired, can also contain minor amounts of wetting or emulsifyingagents, or pH buffering agents. These compositions can take the form ofsolutions, suspensions, emulsion, tablets, pills, capsules, powders,sustained-release formulations and the like. Oral formulation caninclude standard carriers such as pharmaceutical grades of mannitol,lactose, starch, magnesium stearate, sodium saccharine, cellulose,magnesium carbonate, etc. Examples of suitable pharmaceutical carriersare described in “Remington's Pharmaceutical Sciences” by E. W. Martin.Such compositions will contain a prophylactically or therapeuticallyeffective amount of the antibody or fragment thereof, preferably inpurified form, together with a suitable amount ofcarrier so as toprovide the form for proper administration to the patient. Theformulation should suit the mode of administration.

In a preferred embodiment, the composition is formulated in accordancewith routine procedures as a pharmaceutical composition adapted forintravenous administration to human beings. Typically, compositions forintravenous administration are solutions in sterile isotonic aqueousbuffer. Where necessary, the composition may also include a solubilizingagent and a local anesthetic such as lignocamne to ease pain at the siteof the injection.

Generally, the ingredients of compositions of the invention are suppliedeither separately or mixed together in unit dosage form, for example, asa dry lyophilized powder or water free concentrate in a hermeticallysealed container such as an ampoule or sachette indicating the quantityof active agent. Where the composition is to be administered byinfusion, it can be dispensed with an infusion bottle containing sterilepharmaceutical grade water or saline. Where the composition isadministered by injection, an ampoule of sterile water for injection orsaline can be provided so that the ingredients may be mixed prior toadministration.

The compositions of the invention can be formulated as neutral or saltforms. Pharmaceutically acceptable salts include those formed withanions such as those derived from hydrochloric, phosphoric, acetic,oxalic, tartaric acids, etc., and those formed with cations such asthose derived from sodium, potassium, ammonium, calcium, ferrichydroxides, isopropylamine, triethylamine, 2-ethylamino ethanol,histidine, procaine, etc.

The amount of the composition of the invention which will be effectivein the treatment, prevention or amelioration of one or more symptomsassociated with a RSV infection can be determined by standard clinicaltechniques. For example, the dosage of the composition which will beeffective in the treatment, prevention or amelioration of one or moresymptoms associated with a RSV infection can be determined byadministering the composition to a cotton rat, measuring the RSV titerafter challenging the cotton rat with 10⁵ pfu of RSV and comparing theRSV titer to that obtain for a cotton rat not administered thecomposition. Accordingly, a dosage that results in a 2 log decrease or a99% reduction in RSV titer in the cotton rat challenged with 10⁵ pfu ofRSV relative to the cotton rat challenged with 10⁵ pfu of RSV but notadministered the composition is the dosage of the composition that canbe administered to a human for the treatment, prevention or ameliorationof symptoms associated with RSV infection. The dosage of the compositionwhich will be effective in the treatment, prevention or amelioration ofone or more symptoms associated with a RSV infection can be determinedby administering the composition to an animal model (e.g., a cotton rator monkey) and measuring the serum titer of antibodies or fragmentsthereof that immunospecifically bind to a RSV antigen. Accordingly, adosage of the composition that results in a serum titer of at least 1μg/ml, preferably 2 μg/ml, 5 μg/ml, 10 μg/ml, 20 μg/ml, 25 μg/ml, atleast 35 μg/ml, at least 40 μg/ml, at least 50 μg/ml, at least 75 μg/ml,at least 100 μg/ml, at least 125 μg/ml, at least 150 μg/ml, at least 200μg/ml, at least 250 μg/ml, at least 300 μg/ml, at least 350 μg/ml, atleast 400 μg/ml, or at least 450 μg/ml can be administered to a humanfor the treatment, prevention or amelioration of one or more symptomsassociated with RSV infection. In addition, in vitro assays mayoptionally be employed to help identify optimal dosage ranges.

The precise dose to be employed in the formulation will also depend onthe route of administration, and the seriousness of the RSV infection,and should be decided according to the judgment of the practitioner andeach patient's circumstances. Effective doses may be extrapolated fromdose-response curves derived from in vitro or animal model (e.g., thecotton rat or Cynomolgous monkey) test systems.

For antibodies, the dosage administered to a patient is typically 0.1mg/kg to 100 mg/kg of the patient's body weight. Preferably, the dosageadministered to a patient is between 0.1 mg/kg and 20 mg/kg of thepatient's body weight, more preferably 1 mg/kg to 10 mg/kg of thepatient's body weight. Generally, human antibodies have a longerhalf-life within the human body than antibodies from other species dueto the immune response to the foreign polypeptides. Thus, lower dosagesof human antibodies and less frequent administration is often possible.Further, the dosage and frequency of administration of antibodies of theinvention or fragments thereof may be reduced by enhancing uptake andtissue penetration (e.g., into the lung) of the antibodies bymodifications such as, for example, lipidation.

In a specific embodiment, antibodies of the invention or fragmentsthereof, or compositions comprising antibodies of the invention orfragments thereof are administered once a month just prior to or duringthe RSV season. In another embodiment, antibodies of the invention orfragments thereof, or compositions comprising antibodies of theinvention or fragments thereof are administered every two months justprior to or during the RSV season. In yet another embodiment, antibodiesof the invention or fragments thereof, or compositions comprisingantibodies of the invention or fragments thereof are administered oncejust prior to or during the RSV season. The term “RSV season” refers tothe season when RSV infection is most likely to occur. Typically, theRSV season in the northern hemisphere commences in November and laststhrough April.

In one embodiment, approximately 5 mg/kg or less (preferably 1.5 mg/kgor less) of an antibody or fragment thereof which immunospecificallybinds to a RSV antigen with a higher avidity and/or higher affinity thanpreviously known antibodies such as, e.g., SYNAGIS®, is administeredfive times, 3 times, or 1 to 2 times during a RSV season to a mammal,preferably a human. In another embodiment, approximately 1.5 mg/kg of anantibody or a fragment thereof which immunospecifically binds to a RSVantigen with a higher avidity and/or a higher affinity than knownantibodies such as, e.g., SYNAGIS®, is administered monthly five timesduring an RSV season to a mammal, preferably a human, intramuscularly.In another embodiment, 3 mg/kg of an antibody or a fragment thereofwhich immunospecifically binds to a RSV antigen with a higher avidityand/or a higher affinity than known antibodies such as, e.g., SYNAGIS®is administered monthly three times during an RSV season to a mammal,preferably a human, intramuscularly. In yet another embodiment, 5 mg/kgof an antibody or a fragment thereof which immunospecifically binds to aRSV antigen with a higher avidity and/or a higher affinity than knownantibodies such as, e.g., SYNAGIS® is administered monthly one to twotimes during an RSV season to a mammal, preferably a human,intramuscularly.

In a specific embodiment, 15 mg/kg of HL-SYNAGIS or an antigen-bindingfragment thereof is administered to a mammal, preferably a human,intramuscularly five times during an RSV season. In another embodiment,approximately 5 mg/kg or less (preferably 1.5 mg/kg or less) of anantibody or fragment thereof which immunospecifically binds to a RSVantigen with a higher avidity and/or higher affinity than previouslyknown antibodies such as, e.g., SYNAGIS®, is administered five times, 3times, or 1 to 2 times during a RSV season to a mammal, preferably ahuman. In another embodiment, 3 mg/kg of antibody or a fragment thereofwhich immunospecifically binds to a RSV antigen with a higher avidityand/or a higher affinity known antibodies such as, e.g., SYNAGIS® andwhich has an increased in vivo half-life is administered monthly threetimes during an RSV season to a mammal, preferably a human,intramuscularly. In another embodiment, 5 mg/kg of antibody or afragment thereof which immunospecifically binds to a RSV antigen with ahigher avidity and/or a higher affinity than known antibodies such as,e.g., SYNAGIS® and which has an increased in vivo half-life isadministered to a mammal, preferably a human, intramuscularly twicetimes during an RSV season.

In a specific embodiment, an approximately 15 mg/kg bolus of SYNAGIS® oran antigen-binding fragment thereof not in a sustained releaseformulation is administered to a mammal, preferably a human, and after acertain period of time less than 15 mg/kg (preferably 5 mg/kg or less,more preferably 3 mg/kg or less, and most preferably 1.5 mg/kg or less)of SYNAGIS® or an antibody fragment in a sustained release isadministered to said mammal intramuscularly two, three or four timesduring an RSV season. In accordance with this embodiment, a certainperiod of time can be 1 to 5 days, a week, two weeks, or a month. Inanother embodiment, approximately 15 mg/kg or less (preferably at least2 mg/kg, at least 5 mg/kg, or at least 10 mg/kg) of SYNAGIS® or anantigen-binding fragment thereof in a sustained release formulation isadministered to a mammal, preferably a human, intramuscularly two, threeor four times during an RSV season.

In another embodiment, approximately 15 mg/kg or less (preferably atleast 2 mg/kg, at least 5 mg/kg, or at least 10 mg/kg) of one or moreantibodies or fragments thereof which immunospecifically bind to one ormore RSV antigens is administered to the lungs of a mammal by pulmonarydelivery and then after a certain period of time (e.g., 15 minutes, 30minutes, 45 minutes, 1 hour, 6 hours, 12 hours, 1 day, 5 days, 10 days,20 days, 25 days, 30 days, or 40 days) approximately 15 mg/kg or less ofone or more said antibodies or antibody fragments is administeredintramusclarly said mammal. In another embodiment, approximately 15mg/kg or less (preferably at least 2 mg/kg, at least 5 mg/kg, or atleast 10 mg/kg) of one or more antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens is administered to amammal intramusclarly and then after a certain period of time (e.g., 15minutes, 30 minutes, 45 minutes, 1 hour, 6 hours, 12 hours, 1 day, 5days, 10 days, 20 days, 25 days, 30 days, or 40 days) approximately 15mg/kg or less of one or more said antibodies or antibody fragments isadministered to the lungs of said mammal.

5.3.1. Gene Therapy

In a specific embodiment, nucleic acids comprising sequences encodingantibodies or functional derivatives thereof, are administered to treat,prevent or ameliorate one or more symptoms associated with RSVinfection, by way of gene therapy. Gene therapy refers to therapyperformed by the administration to a subject of an expressed orexpressible nucleic acid. In this embodiment of the invention, thenucleic acids produce their encoded antibody or antibody fragment thatmediates a prophylactic or therapeutic effect.

Any of the methods for gene therapy available in the art can be usedaccording to the present invention. Exemplary methods are describedbelow.

For general reviews of the methods of gene therapy, see Goldspiel etal., 1993, Clinical Pharmacy 12:488-505; Wu and Wu, 1991, Biotherapy3:87-95; Tolstoshev, 1993, Ann. Rev. Pharmacol. Toxicol. 32:573-596;Mulligan, Science 260:926-932 (1993); and Morgan and Anderson, 1993,Ann. Rev. Biochem. 62:191-217; May, 1993, TIBTECH 11(5): 155-215.Methods commonly known in the art of recombinant DNA technology whichcan be used are described in Ausubel et al. (eds.), Current Protocols inMolecular Biology, John Wiley & Sons, NY (1993); and Kriegler, GeneTransfer and Expression, A Laboratory Manual, Stockton Press, NY (1990).

In a preferred aspect, a composition of the invention comprises nucleicacids encoding an antibody, said nucleic acids being part of anexpression vector that expresses the antibody or fragments or chimericproteins or heavy or light chains thereof in a suitable host. Inparticular, such nucleic acids have promoters, preferably heterologouspromoters, operably linked to the antibody coding region, said promoterbeing inducible or constitutive, and, optionally, tissue-specific. Inanother particular embodiment, nucleic acid molecules are used in whichthe antibody coding sequences and any other desired sequences areflanked by regions that promote homologous recombination at a desiredsite in the genome, thus providing for intrachromosomal expression ofthe antibody encoding nucleic acids (Koller and Smithies, 1989, Proc.Natl. Acad. Sci. USA 86:8932-8935; Zijlstra et al., 1989, Nature342:435-438). In specific embodiments, the expressed antibody moleculeis a single chain antibody; alternatively, the nucleic acid sequencesinclude sequences encoding both the heavy and light chains, or fragmentsthereof, of the antibody.

Delivery of the nucleic acids into a subject may be either direct, inwhich case the subject is directly exposed to the nucleic acid ornucleic acid-carrying vectors, or indirect, in which case, cells arefirst transformed with the nucleic acids in vitro, then transplantedinto the subject. These two approaches are known, respectively, as invivo or ex vivo gene therapy.

In a specific embodiment, the nucleic acid sequences are directlyadministered in vivo, where it is expressed to produce the encodedproduct. This can be accomplished by any of numerous methods known inthe art, e.g., by constructing them as part of an appropriate nucleicacid expression vector and administering it so that they becomentracellular, e.g., by infection using defective or attenuatedretrovirals or other viral vectors (see U.S. Pat. No. 4,980,286), or bydirect injection of naked DNA, or by use of icroparticle bombardment(e.g., a gene gun; Biolistic, Dupont), or coating with lipids orcell-surface receptors or transfecting agents, encapsulation inliposomes, microparticles, or microcapsules, or by administering them inlinkage to a peptide which is known to enter the nucleus, byadministering it in linkage to a ligand subject to receptor-mediatedendocytosis (see, e.g., Wu and Wu, 1987, J. Biol. Chem. 262:4429-4432)(which can be used to target cell types specifically expressing thereceptors), etc. In another embodiment, nucleic acid-ligand complexescan be formed in which the ligand comprises a fusogenic viral peptide todisrupt endosomes, allowing the nucleic acid to avoid lysosomaldegradation. In yet another embodiment, the nucleic acid can be targetedin vivo for cell specific uptake and expression, by targeting a specificreceptor (see, e.g., PCT Publications WO 92/06180; WO 92/22635; WO92/20316; WO93/14188, WO 93/20221). Alternatively, the nucleic acid can beintroduced intracellularly and incorporated within host cell DNA forexpression, by homologous recombination (Koller and Smithies, 1989,Proc. Natl. Acad. Sci. USA 86:8932-8935; and Zijlstra et al., 1989,Nature 342:435-438).

In a specific embodiment, viral vectors that contains nucleic acidsequences encoding an antibody of the invention or fragments thereof areused. For example, a retroviral vector can be used (see Miller et al.,1993, Meth. Enzymol. 217:581-599). These retroviral vectors contain thecomponents necessary for the correct packaging of the viral genome andintegration into the host cell DNA. The nucleic acid sequences encodingthe antibody to be used in gene therapy are cloned into one or morevectors, which facilitates delivery of the gene into a subject. Moredetail about retroviral vectors can be found in Boesen et al., 1994,Biotherapy 6:291-302, which describes the use of a retroviral vector todeliver the mdr 1 gene to hematopoietic stem cells in order to make thestem cells more resistant to chemotherapy. Other references illustratingthe use of retroviral vectors in gene therapy are: Clowes et al., 1994,J. Clin. Invest. 93:644-651; Klein et al., 1994, Blood 83:1467-1473;Salmons and Gunzberg, 1993, Human Gene Therapy 4:129-141; and Grossmanand Wilson, 1993, Curr. Opin. in Genetics and Devel. 3:110-114.

Adenoviruses are other viral vectors that can be used in gene therapy.Adenoviruses are especially attractive vehicles for delivering genes torespiratory epithelia. Adenoviruses naturally infect respiratoryepithelia where they cause a mild disease. Other targets foradenovirus-based delivery systems are liver, the central nervous system,endothelial cells, and muscle. Adenoviruses have the advantage of beingcapable of infecting non-dividing cells. Kozarsky and Wilson, 1993,Current Opinion in Genetics and Development 3:499-503 present a reviewof adenovirus-based gene therapy. Bout et al., 1994, Human Gene Therapy5:3-10 demonstrated the use of adenovirus vectors to transfer genes tothe respiratory epithelia of rhesus monkeys. Other instances of the useof adenoviruses in gene therapy can be found in Rosenfeld et al., 1991,Science 252:431-434; Rosenfeld et al., 1992, Cell 68:143-155;Mastrangeli et al., 1993, J. Clin. Invest. 91:225-234; PCT PublicationWO94/12649; and Wang et al., 1995, Gene Therapy 2:775-783. In apreferred embodiment, adenovirus vectors are used.

Adeno-associated virus (AAV) has also been proposed for use in genetherapy (Walsh et al., 1993, Proc. Soc. Exp. Biol. Med. 204:289-300; andU.S. Pat. No. 5,436,146).

Another approach to gene therapy involves transferring a gene to cellsin tissue culture by such methods as electroporation, lipofection,calcium phosphate mediated transfection, or viral infection. Usually,the method of transfer includes the transfer of a selectable marker tothe cells. The cells are then placed under selection to isolate thosecells that have taken up and are expressing the transferred gene. Thosecells are then delivered to a subject.

In this embodiment, the nucleic acid is introduced into a cell prior toadministration in vivo of the resulting recombinant cell. Suchintroduction can be carried out by any method known in the art,including but not limited to transfection, electroporation,microinjection, infection with a viral or bacteriophage vectorcontaining the nucleic acid sequences, cell fusion, chromosome-mediatedgene transfer, microcellmediated gene transfer, spheroplast fusion, etc.Numerous techniques are known in the art for the introduction of foreigngenes into cells (see, e.g., Loeffler and Behr, 1993, Meth. Enzymol.217:599-618; Cohen et al., 1993, Meth. Enzymol. 217:618-644; Clin.Pharma. Ther. 29:69-92 (1985)) and may be used in accordance with thepresent invention, provided that the necessary developmental andphysiological functions of the recipient cells are not disrupted. Thetechnique should provide for the stable transfer of the nucleic acid tothe cell, so that the nucleic acid is expressible by the cell andpreferably heritable and expressible by its cell progeny.

The resulting recombinant cells can be delivered to a subject by variousmethods known in the art. Recombinant blood cells (e.g., hematopoieticstem or progenitor cells) are preferably administered intravenously. Theamount of cells envisioned for use depends on the desired effect,patient state, etc., and can be determined by one skilled in the art.

Cells into which a nucleic acid can be introduced for purposes of genetherapy encompass any desired, available cell type, and include but arenot limited to epithelial cells, endothelial cells, keratinocytes,fibroblasts, muscle cells, hepatocytes; blood cells such as Tlymphocytes, B lymphocytes, monocytes, macrophages, neutrophils,eosinophils, megakaryocytes, granulocytes; various stem or progenitorcells, in particular hematopoietic stem or progenitor cells, e.g., asobtained from bone marrow, umbilical cord blood, peripheral blood, fetalliver, etc.

In a preferred embodiment, the cell used for gene therapy is autologousto the subject.

In an embodiment in which recombinant cells are used in gene therapy,nucleic acid sequences encoding an antibody or fragment thereof areintroduced into the cells such that they are expressible by the cells ortheir progeny, and the recombinant cells are then administered in vivofor therapeutic effect. In a specific embodiment, stem or progenitorcells are used. Any stem and/or progenitor cells which can be isolatedand maintained in vitro can potentially be used in accordance with thisembodiment of the present invention (see e.g., PCT Publication WO94/08598; Stemple and Anderson, 1992, Cell 7 1:973-985; Rheinwald, 1980,Meth. Cell Bio. 21A:229; and Pittelkow and Scott, 1986, Mayo ClinicProc. 61:771).

In a specific embodiment, the nucleic acid to be introduced for purposesof gene therapy comprises an inducible promoter operably linked to thecoding region, such that expression of the nucleic acid is controllableby controlling the presence or absence of the appropriate inducer oftranscription.

5.4. Antibody Characterization and Demonstration of Therapeutic orProphylactic Utility

Antibodies of the present invention or fragments thereof may becharacterized in a variety of ways. In particular, antibodies of theinvention or fragments thereof may be assayed for the ability toimmunospecifically bind to a RSV antigen. Such an assay may be performedin solution (e.g., Houghten, 1992, Bio/Techniques 13:412-421), on beads(Lam, 1991, Nature 354:82-84), on chips (Fodor, 1993, Nature364:555-556), on bacteria (U.S. Pat. No. 5,223,409), on spores (U.S.Pat. Nos. 5,571,698; 5,403,484; and 5,223,409), on plasmids (Cull etal., 1992, Proc. Natl. Acad. Sci. USA 89:1865-1869) or on phage (Scottand Smith, 1990, Science 249:386-390; Devlin, 1990, Science 249:404-406;Cwirla et al., 1990, Proc. Natt. Acad. Sci. USA 87:6378-6382; andFelici, 1991, J. Mol. Biol. 222:301-310) (each of these references isincorporated herein in its entirety by reference). Antibodies orfragments thereof that have been identified to immunospecifically bindto a RSV antigen or a fragment thereof can then be assayed for theirspecificity and affinity for a RSV antigen.

The antibodies of the invention or fragments thereof may be assayed forimmunospecific binding to a RSV antigen and cross-reactivity with otherantigens by any method known in the art. Immunoassays which can be usedto analyze immunospecific binding and cross-reactivity include, but arenot limited to, competitive and non-competitive assay systems usingtechniques such as western blots, radioimmunoassays, ELISA (enzymelinked immunosorbent assay), “sandwich” immunoassays,immunoprecipitation assays, precipitin reactions, gel diffusionprecipitin reactions, immunodiffusion assays, agglutination assays,complement-fixation assays, immunoradiometric assays, fluorescentimmunoassays, protein A immunoassays, to name but a few. Such assays areroutine and well known in the art (see, e.g., Ausubel et al, eds, 1994,Current Protocols in Molecular Biology, Vol. 1, John Wiley & Sons, Inc.,New York, which is incorporated by reference herein in its entirety).Exemplary immunoassays are described briefly below (but are not intendedby way of limitation).

Immunoprecipitation protocols generally comprise lysing a population ofcells in a lysis buffer such as RIPA buffer (1% NP-40 or Triton X-100,1% sodium deoxycholate, 0.1% SDS, 0.15 M NaCl, 0.01 M sodium phosphateat pH 7.2, 1% Trasylol) supplemented with protein phosphatase and/orprotease inhibitors (e.g., EDTA, PMSF, aprotinin, sodium vanadate),adding the antibody of interest to the cell lysate, incubating for aperiod of time (e.g., 1 to 4 hours) at 40° C., adding protein A and/orprotein G sepharose beads to the cell lysate, incubating for about anhour or more at 40° C., washing the beads in lysis buffer andresuspending the beads in SDS/sample buffer. The ability of the antibodyof interest to immunoprecipitate a particular antigen can be assessedby, e.g., western blot analysis. One of skill in the art would beknowledgeable as to the parameters that can be modified to increase thebinding of the antibody to an antigen and decrease the background (e.g.,pre-clearing the cell lysate with sepharose beads). For furtherdiscussion regarding immunoprecipitation protocols see, e.g., Ausubel etal, eds, 1994, Current Protocols in Molecular Biology, Vol. 1, JohnWiley & Sons, Inc., New York at 10.16.1.

Western blot analysis generally comprises preparing protein samples,electrophoresis of the protein samples in a polyacrylamide gel (e.g.,8%-20% SDS-PAGE depending on the molecular weight of the antigen),transferring the protein sample from the polyacrylamide gel to amembrane such as nitrocellulose, PVDF or nylon, blocking the membrane inblocking solution (e.g., PBS with 3% BSA or non-fat milk), washing themembrane in washing buffer (e.g., PBS-Tween 20), blocking the membranewith primary antibody (the antibody of interest) diluted in blockingbuffer, washing the membrane in washing buffer, blocking the membranewith a secondary antibody (which recognizes the primary antibody, e.g.,an anti-human antibody) conjugated to an enzymatic substrate (e.g.,horseradish peroxidase or alkaline phosphatase) or radioactive molecule(e.g., ³²P or ¹²⁵I) diluted in blocking buffer, washing the membrane inwash buffer, and detecting the presence of the antigen. One of skill inthe art would be knowledgeable as to the parameters that can be modifiedto increase the signal detected and to reduce the background noise. Forfurther discussion regarding western blot protocols see, e.g., Ausubelet al, eds, 1994, Current Protocols in Molecular Biology, Vol. 1, JohnWiley & Sons, Inc., New York at 10.8.1.

ELISAs comprise preparing antigen, coating the well of a 96 wellmicrotiter plate with the antigen, adding the antibody of interestconjugated to a detectable compound such as an enzymatic substrate(e.g., horseradish peroxidase or alkaline phosphatase) to the well andincubating for a period of time, and detecting the presence of theantigen. In ELISAs the antibody of interest does not have to beconjugated to a detectable compound; instead, a second antibody (whichrecognizes the antibody of interest) conjugated to a detectable compoundmay be added to the well. Further, instead of coating the well with theantigen, the antibody may be coated to the well. In this case, a secondantibody conjugated to a detectable compound may be added following theaddition of the antigen of interest to the coated well. One of skill inthe art would be knowledgeable as to the parameters that can be modifiedto increase the signal detected as well as other variations of ELISAsknown in the art. For further discussion regarding ELISAs see, e.g.,Ausubel et al, eds, 1994, Current Protocols in Molecular Biology, Vol.1, John Wiley & Sons, Inc., New York at 11.2.1.

The binding affinity of an antibody to an antigen and the off-rate of anantibody-antigen interaction can be determined by competitive bindingassays. One example of a competitive binding assay is a radioimmunoassaycomprising the incubation of labeled antigen (e.g., ³H or ¹²⁵I) with theantibody of interest in the presence of increasing amounts of unlabeledantigen, and the detection of the antibody bound to the labeled antigen.The affinity of the antibody of the present invention or a fragmentthereof for a RSV antigen and the binding off-rates can be determinedfrom the data by scatchard plot analysis. Competition with a secondantibody can also be determined using radioimmunoassays. In this case, aRSV antigen is incubated with an antibody of the present invention or afragment thereof conjugated to a labeled compound (e.g., ³H or ¹²⁵I) inthe presence of increasing amounts of an unlabeled second antibody.

In a preferred embodiment, BIAcore kinetic analysis is used to determinethe binding on and off rates of antibodies or fragments thereof to a RSVantigen. BIAcore kinetic nalysis comprises analyzing the binding anddissociation of a RSV antigen from chips with mmobilized antibodies orfragments thereof on their surface (see the Example section infra).

The antibodies of the invention or fragments thereof can also be assayedfor their ability to inhibit the binding of RSV to its host cellreceptor using techniques known to hose of skill in the art. Forexample, cells expressing the receptor for RSV can be contacted with RSVin the presence or absence of an antibody or fragment thereof and thebility of the antibody or fragment thereof to inhibit RSV's binding canmeasured by, for example, flow cytometry or a scintillation assay. RSV(e.g., a RSV antigen such as F glycoprotein or G glycoprotein) or theantibody or antibody fragment can be labeled with a detectable compoundsuch as a radioactive label (e.g., ³²P, ³⁵S, and ¹²⁵I) or a fluorescentlabel (e.g., fluorescein isothiocyanate, rhodamine, phycoerythrin,phycocyanin, allophycocyanin, o-phthaldehyde and fluorescamine) toenable detection of an interaction between RSV and its host cellreceptor. Alternatively, the ability of antibodies or fragments thereofto inhibit RSV from binding to its receptor can be determined incell-free assays. For example, RSV or a RSV antigen such as Gglycoprotein can be contacted with an antibody or fragment thereof andthe ability of the antibody or antibody fragment to inhibit RSV or theRSV antigen from binding to its host cell receptor can be determined.Preferably, the antibody or the antibody fragment is immobilized on asolid support and RSV or a RSV antigen is labeled with a detectablecompound. Alternatively, RSV or a RSV antigen is immobilized on a solidsupport and the antibody or fragment thereof is labeled with adetectable compound. RSV or a RSV antigen may be partially or completelypurified (e.g., partially or completely free of other polypeptides) orpart of a cell lysate. Further, an RSV antigen may be a fusion proteincomprising the RSV antigen and a domain such asglutathionine-S-transferase. Alternatively, an RSV antigen can bebiotinylated using techniques well known to those of skill in the art(e.g., biotinylation kit, Pierce Chemicals; Rockford, Ill.).

The antibodies of the invention or fragments thereof can also be assayedfor their ability to inhibit or downregulate RSV replication usingtechniques known to those of skill in the art. For example, RSVreplication can be assayed by a plaque assay such as described, e.g., byJohnson et al., 1997, Journal of Infectious Diseases 176:1215-1224. Theantibodies of the invention or fragments thereof can also be assayed fortheir ability to inhibit or downregulate the expression of RSVpolypeptides. Techniques known to those of skill in the art, including,but not limited to, Western blot analysis, Northern blot analysis, andRT-PCR can be used to measure the expression of RSV polypeptides.Further, the antibodies of the invention or fragments thereof can beassayed for their ability to prevent the formation of syncytia.

The antibodies of the invention or fragments thereof are preferablytested in vitro, and then in vivo for the desired therapeutic orprophylactic activity, prior to use in humans. For example, in vitroassays which can be used to determine whether administration of aspecific antibody or composition of the present invention is indicated,include in vitro cell culture assays in which a subject tissue sample isgrown in culture, and exposed to or otherwise administered an antibodyor composition of the present invention, and the effect of such anantibody or composition of the present invention upon the tissue sampleis observed. In various specific embodiments, in vitro assays can becarried out with representative cells of cell types involved in a RSVinfection (e.g., respiratory epithelial cells), to determine if anantibody or composition of the present invention has a desired effectupon such cell types. Preferably, the antibodies or compositions of theinvention are also tested in in vitro assays and animal model systemsprior to administration to humans. In a specific embodiment, cotton ratsare administered an antibody the invention or fragment thereof, or acomposition of the invention, challenged with 10⁵ pfu of RSV, and fouror more days later the rats are sacrificed and RSV titer and anti-RSVantibody serum titer is determined. Further, in accordance with thisembodiment, the tissues (e.g., the lung tissues) from the sacrificedrats can be examined for histological changes.

In accordance with the invention, clinical trials with human subjectsneed not be performed in order to demonstrate the prophylactic and/ortherapeutic efficacy of antibodies of the invention or fragmentsthereof. In vitro and animal model studies using the antibodies orfragments thereof can be extrapolated to humans and are sufficient fordemonstrating the prophylactic and/or therapeutic utility of saidantibodies or antibody fragments.

Antibodies or compositions of the present invention for use in therapycan be tested for their toxicity in suitable animal model systems,including but not limited to rats, mice, cows, monkeys, and rabbits. Forin vivo testing of an antibody or composition's toxicity any animalmodel system known in the art may be used.

Efficacy in treating or preventing viral infection may be demonstratedby detecting the ability of an antibody or composition of the inventionto inhibit the replication of the virus, to inhibit transmission orprevent the virus from establishing itself in its host, to reduce theincidence of RSV infection, or to prevent, ameliorate or alleviate oneor more symptoms associated with RSV infection. The treatment isconsidered therapeutic if there is, for example, a reduction is viralload, amelioration of one or more symptoms, a reduction in the durationof a RSV infection, or a decrease in mortality and/or morbidityfollowing administration of an antibody or composition of the invention.Further, the treatment is considered therapeutic if there is an increasein the immune response following the administration of one or moreantibodies or fragments thereof which immunospecifically bind to one ormore RSV antigens.

Antibodies or compositions of the invention can be tested in vitro andin vivo for the ability to induce the expression of cytokines such asIFN-α, IFN-β, IFN-γ, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9,IL-10, IL-12 and IL-15. Techniques known to those of skill in the artcan be used to measure the level of expression of cytokines. Forexample, the level of expression of cytokines can be measured byanalyzing the level of RNA of cytokines by, for example, RT-PCR andNorthern blot analysis, and by analyzing the level of cytokines by, forexample, immunoprecipitation followed by western blot analysis andELISA. In a preferred embodiment, an antibody or composition of theinvention is tested for its ability to induce the expression of IFN-γ.

Antibodies or compositions of the invention can be tested in vitro andin vivo for their ability to modulate the biological activity of immunecells, preferably human immune cells (e.g., T-cells, B-cells, andNatural Killer cells). The ability of an antibody or composition of theinvention to modulate the biological activity of immune cells can beassessed by detecting the expression of antigens, detecting theproliferation of immune cells, detecting the activation of signalingmolecules, detecting the effector function of immune cells, or detectingthe differentiation of immune cells. Techniques known to those of skillin the art can be used for measuring these activities. For example,cellular proliferation can be assayed by ³H-thymidine incorporationassays and trypan blue cell counts. Antigen expression can be assayed,for example, by immunoassays including, but are not limited to,competitive and non-competitive assay systems using techniques such aswestern blots, immunohistochemistry radioimmunoassays, ELISA (enzymelinked immunosorbent assay), “sandwich” immunoassays,immunoprecipitation assays, precipitin reactions, gel diffusionprecipitin reactions, immunodiffusion assays, agglutination assays,complement-fixation assays, immunoradiometric assays, fluorescentimmunoassays, protein A immunoassays and FACS analysis. The activationof signaling molecules can be assayed, for example, by kinase assays andelectrophoretic shift assays (EMSAs).

Antibodies or compositions of the invention can also be tested for theirability to inhibit viral replication or reduce viral load in in vitro,ex vivo and in vivo assays. Antibodies or compositions of the inventioncan also be tested for their ability to decrease the time course of RSVinfection. Antibodies or compositions of the invention can also betested for their ability to increase the survival period of humanssuffering from RSV infection by at least 25%, preferably at least 50%,at least 60%, at least 75%, at least 85%, at least 95%, or at least 99%.Further, antibodies or compositions of the invention can be tested fortheir ability reduce the hospitalization period of humans suffering fromRSV infection by at least 60%, preferably at least 75%, at least 85%, atleast 95%, or at least 99%. Techniques known to those of skill in theart can be used to analyze the function of the antibodies orcompositions of the invention in vivo.

5.5. Diagnostic Uses of Antibodies

Labeled antibodies, fragments and derivatives and analogs thereof, whichimmunospecifically bind to a RSV antigen can be used for diagnosticpurposes to detect, diagnose, or monitor a RSV infection. The inventionprovides for the detection of a RSV infection, comprising: (a) assayingthe expression of a RSV antigen in cells or a tissue sample of a subjectusing one or more antibodies or fragments thereof thatimmunospecifically bind to the RSV antigen; and (b) comparing the levelof the RSV antigen with a control level, e.g., levels in normal tissuesamples not infected with RSV, whereby an increase in the assayed levelof RSV antigen compared to the control level of the RSV antigen isindicative of a RSV infection.

The invention provides a diagnostic assay for diagnosing a RSVinfection, comprising: (a) assaying for the level of a RSV antigen incells or a tissue sample of an individual using one or more antibodiesor fragments thereof that immunospecifically bind to a RSV antigen; and(b) comparing the level of the RSV antigen with a control level, e.g.,levels in normal tissue samples not infected with RSV, whereby anincrease in the assayed RSV antigen level compared to the control levelof the RSV antigen is indicative of a RSV infection. A more definitivediagnosis of RSV infection may allow health professionals to employpreventative measures or aggressive treatment earlier thereby preventingthe development or further progression of RSV infection.

Antibodies of the invention or fragments thereof can be used to assayRSV antigen levels in a biological sample using classicalimmunohistological methods as described herein or as known to those ofskill in the art (e.g., see Jalkanen et al., 1985, J. Cell. Biol.101:976-985; and Jalkanen et al., 1987, J. Cell. Biol. 105:3087-3096).Other antibody-based methods useful for detecting protein geneexpression include immunoassays, such as the enzyme linked immunosorbentassay (ELISA) and the radioimmunoassay (RIA). Suitable antibody assaylabels are known in the art and include enzyme labels, such as, glucoseoxidase; radioisotopes, such as iodine (125I, ¹²¹I), carbon (¹⁴C),sulfur (³⁵S), tritium (³H), indium (¹²¹In), and technetium (⁹⁹Tc);luminescent labels, such as luminol; and fluorescent labels, such asfluorescein and rhodamine, and biotin.

One aspect of the invention is the detection and diagnosis of a RSVinfection in a human. In one embodiment, diagnosis comprises: a)administering (for example, parenterally, subcutaneously, orintraperitoneally) to a subject an effective amount of a labeledantibody or fragment thereof that immunospecifically binds to a RSVantigen; b) waiting for a time interval following the administering forpermitting the labeled antibody or fragment thereof to preferentiallyconcentrate at sites in the subject (e.g., the lungs) where the RSVantigen is expressed (and for unbound labeled molecule to be cleared tobackground level); c) determining background level; and d) detecting thelabeled antibody or fragment thereof in the subject, such that detectionof labeled antibody or fragment thereof above the background levelindicates that the subject has a RSV infection. Background level can bedetermined by various methods including, comparing the amount of labeledmolecule detected to a standard value previously determined for aparticular system.

It will be understood in the art that the size of the subject and theimaging system used will determine the quantity of imaging moiety neededto produce diagnostic images. In the case of a radioisotope moiety, fora human subject, the quantity of radioactivity injected will normallyrange from about 5 to 20 millicuries of ⁹⁹Tc. The labeled antibody orantibody fragment will then preferentially accumulate at the location ofcells which contain the specific protein. In vivo tumor imaging isdescribed in S. W. Burchiel et al., “Immunopharmacokinetics ofRadiolabeled Antibodies and Their Fragments.” (Chapter 13 in TumorImaging: The Radiochemical Detection of Cancer, S. W. Burchiel and B. A.Rhodes, eds., Masson Publishing Inc. (1982).

Depending on several variables, including the type of label used and themode of administration, the time interval following the administrationfor permitting the labeled molecule to preferentially concentrate atsites in the subject and for unbound labeled molecule to be cleared tobackground level is 6 to 48 hours or 6 to 24 hours or 6 to 12 hours. Inanother embodiment the time interval following administration is 5 to 20days or 5 to 10 days.

In one embodiment, monitoring of a RSV infection is carried out byrepeating the method for diagnosing the RSV infection, for example, onemonth after initial diagnosis, six months after initial diagnosis, oneyear after initial diagnosis, etc.

Presence of the labeled molecule can be detected in the subject usingmethods known 35 in the art for in vivo scanning. These methods dependupon the type of label used. Skilled rtisans will be able to determinethe appropriate method for detecting a particular label ethods anddevices that may be used in the diagnostic methods of the inventioninclude, ut are not limited to, computed tomography (CT), whole bodyscan such as position mission tomography (PET), magnetic resonanceimaging (MRI), and sonography.

In a specific embodiment, the molecule is labeled with a radioisotopeand is detected in the patient using a radiation responsive surgicalinstrument (Thurston et al., U.S. Pat. No. 5,441,050). In anotherembodiment, the molecule is labeled with a fluorescent compound and isdetected in the patient using a fluorescence responsive scanninginstrument. In another embodiment, the molecule is labeled with apositron emitting metal and is detected in the patient using positronemission-tomography. In yet another embodiment, the molecule is labeledwith a paramagnetic label and is detected in a patient using magneticresonance imaging (MRI).

5.6. Methods Producing Antibodies

The antibodies of the invention or fragments thereof can be produced byany method known in the art for the synthesis of antibodies, inparticular, by chemical synthesis or preferably, by recombinantexpression techniques.

Polyclonal antibodies to a RSV antigen can be produced by variousprocedures well known in the art. For example, a RSV antigen can beadministered to various host animals including, but not limited to,rabbits, mice, rats, etc. to induce the production of sera containingpolyclonal antibodies specific for the RSV antigen. Various adjuvantsmay be used to increase the immunological response, depending on thehost species, and include but are not limited to, Freund's (complete andincomplete), mineral gels such as aluminum hydroxide, surface activesubstances such as lysolecithin, pluronic polyols, polyanions, peptides,oil emulsions, keyhole limpet hemocyanins, dinitrophenol, andpotentially useful human adjuvants such as BCG (bacille Calmette-Guerin)and corynebacterium parvum. Such adjuvants are also well known in theart.

Monoclonal antibodies can be prepared using a wide variety of techniquesknown in the art including the use of hybridoma, recombinant, and phagedisplay technologies, or a combination thereof. For example, monoclonalantibodies can be produced using hybridoma techniques including thoseknown in the art and taught, for example, in Harlow et al., Antibodies:A Laboratory Manual, (Cold Spring Harbor Laboratory Press, 2nd ed.1988); Hammerling, et al., in: Monoclonal Antibodies and T-CellHybridomas 563-681 (Elsevier, N.Y., 1981) (said references incorporatedby reference in their entireties). The term “monoclonal antibody” asused herein is not limited to antibodies produced through hybridomatechnology. The term “monoclonal antibody” refers to an antibody that isderived from a single clone, including any eukaryotic, prokaryotic, orphage clone, and not the method by which it is produced.

Methods for producing and screening for specific antibodies usinghybridoma technology are routine and well known in the art. Briefly,mice can be immunized with a RSV antigen and once an immune response isdetected, e.g., antibodies specific for the RSV antigen are detected inthe mouse serum, the mouse spleen is harvested and splenocytes isolated.The splenocytes are then fused by well known techniques to any suitablemyeloma cells, for example cells from cell line SP20 available from theATCC. Hybridomas are selected and cloned by limited dilution. Thehybridoma clones are then assayed by methods known in the art for cellsthat secrete antibodies capable of binding a polypeptide of theinvention. Ascites fluid, which generally contains high levels ofantibodies, can be generated by immunizing mice with positive hybridomaclones.

Accordingly, the present invention provides methods of generatingmonoclonal antibodies as well as antibodies produced by the methodcomprising culturing a hybridoma cell secreting an antibody of theinvention wherein, preferably, the hybridoma is generated by fusingsplenocytes isolated from a mouse immunized with a RSV antigen withmyeloma cells and then screening the hybridomas resulting from thefusion for hybridoma clones that secrete an antibody able to bind a RSVantigen.

Antibody fragments which recognize specific RSV epitopes may begenerated by any technique known to those of skill in the art. Forexample, Fab and F(ab′)₂ fragments of the invention may be produced byproteolytic cleavage of immunoglobulin molecules, using enzymes such aspapain (to produce Fab fragments) or pepsin (to produce F(ab′)2fragments). F(ab′)2 fragments contain the variable region, the lightchain constant region and the CH1 domain of the heavy chain. Further,the antibodies of the present invention can also be generated usingvarious phage display methods known in the art.

In phage display methods, functional antibody domains are displayed onthe surface of phage particles which carry the polynucleotide sequencesencoding them. In particular, DNA sequences encoding VH and VL domainsare amplified from animal cDNA libraries (e.g., human or murine cDNAlibraries of lymphoid tissues). The DNA encoding the VH and VL domainsare recombined together with an scFv linker by PCR and cloned into aphagemid vector (e.g., p CANTAB 6 or pComb 3 HSS). The vector iselectroporated in E. coli and the E. coli is infected with helper phage.Phage used in these methods are typically filamentous phage including fdand M13 and the VH and VL domains are usually recombinantly fused toeither the phage gene III or gene VIII. Phage expressing an antigenbinding domain that binds to a RSV antigen of interest can be selectedor identified with antigen, e.g., using labeled antigen or antigen boundor captured to a solid surface or bead examples of phage display methodsthat can be used to make the antibodies of the present invention includethose disclosed in Brinkman et al., 1995, J. Immunol. Methods 182:41-50;Ames et al., 1995, J. Immunol. Methods 184:177-186; Kettleborough etal., 1994, Eur. J. Immunol. 24:952-958; Persic et al., 1997, Gene187:9-18; Burton et al., 1994, Advances in Immunology 57:191-280; PCTapplication No. PCT/GB91/O1 134; PCT publication Nos. WO 90/02809, WO91/10737, WO 92/01047, WO 92/18619, WO 93/1 1236, WO 95/15982, WO95/20401, and WO97/13844; and U.S. Pat. Nos. 5,698,426, 5,223,409,5,403,484, 5,580,717, 5,427,908, 5,750,753, 5,821,047, 5,571,698,5,427,908, 5,516,637, 5,780,225, 5,658,727, 5,733,743 and 5,969,108;each of which is incorporated herein by reference in its entirety.

As described in the above references, after phage selection, theantibody coding regions from the phage can be isolated and used togenerate whole antibodies, including human antibodies, or any otherdesired antigen binding fragment, and expressed in any desired host,including mammalian cells, insect cells, plant cells, yeast, andbacteria, e.g., as described below. Techniques to recombinantly produceFab, Fab′ and F(ab′)₂ fragments can also be employed using methods knownin the art such as those disclosed in PCT publication No. WO 92/22324;Mullinax et al., 1992, BioTechniques 12(6):864-869; Sawai et al., 1995,AJRI 34:26-34; and Better et al., 1988, Science 240:1041-1043 (saidreferences incorporated by reference in their entireties).

To generate whole antibodies, PCR primers including VH or VL nucleotidesequences, a restriction site, and a flanking sequence to protect therestriction site can be used to amplify the VH or VL sequences in scFvclones. Utilizing cloning techniques known to those of skill in the art,the PCR amplified VH domains can be cloned into vectors expressing a VHconstant region, e.g., the human gamma 4 constant region, and the PCRamplified VL domains can be cloned into vectors expressing a VL constantregion, e.g., human kappa or lamba constant regions. Preferably, thevectors for expressing the VH or VL domains comprise an EF-1α promoter,a secretion signal, a cloning site for the variable domain, constantdomains, and a selection marker such as neomycin. The VH and VL domainsmay also cloned into one vector expressing the necessary constantregions. The heavy chain conversion vectors and light chain conversionvectors are then co-transfected into cell lines to generate stable ortransient cell lines that express full-length antibodies, e.g., IgG,using techniques known to those of skill in the art.

For some uses, including in vivo use of antibodies in humans and invitro detection assays, it may be preferable to use human or chimericantibodies. Completely human antibodies are particularly desirable fortherapeutic treatment of human subjects. Human antibodies can be made bya variety of methods known in the art including phage display methodsdescribed above using antibody libraries derived from humanimmunoglobulin sequences. See also U.S. Pat. Nos. 4,444,887 and4,716,111; and PCT publications WO 98/46645, WO 98/50433, WO 98/24893,WO98/16654, WO 96/34096, WO 96/33735, and WO 91/10741; each of which isincorporated herein by reference in its entirety.

Human antibodies can also be produced using transgenic mice which areincapable of expressing functional endogenous immunoglobulins, but whichcan express human immunoglobulin genes. For example, the human heavy andlight chain immunoglobulin gene complexes may be introduced randomly orby homologous recombination into mouse embryonic stem cells.Alternatively, the human variable region, constant region, and diversityregion may be introduced into mouse embryonic stem cells in addition tothe human heavy and light chain genes. The mouse heavy and light chainimmunoglobulin genes may be rendered non-functional separately orsimultaneously with the introduction of human immunoglobulin loci byhomologous recombination. In particular, homozygous deletion of theJ_(H) region prevents endogenous antibody production. The modifiedembryonic stem cells are expanded and microinjected into blastocysts toproduce chimeric mice. The chimeric mice are then be bred to producehomozygous offspring which express human antibodies. The transgenic miceare immunized in the normal fashion with a selected antigen, e.g., allor a portion of a polypeptide of the invention. Monoclonal antibodiesdirected against the antigen can be obtained from the immunized,transgenic mice using conventional hybridoma technology. The humanimmunoglobulin transgenes harbored by the transgenic mice rearrangeduring B cell differentiation, and subsequently undergo class switchingand somatic mutation. Thus, using such a technique, it is possible toproduce therapeutically useful IgG, IgA, IgM and IgE antibodies. For anoverview of this technology for producing human antibodies, see Lonbergand Huszar (1995, Int. Rev. Immunol. 13:65-93). For a detaileddiscussion of this technology for producing human antibodies and humanmonoclonal antibodies and protocols for producing such antibodies, see,e.g., PCT publication Nos. WO 98/24893, WO 96/34096, and WO 96/33735;and U.S. Pat. Nos. 5,413,923, 5,625,126, 5,633,425, 5,569,825,5,661,016, 5,545,806, 5,814,318, and 5,939,598, which are incorporatedby reference herein in their entirety. In addition, companies such asAbgenix, Inc. (Freemont, Calif.) and Genpharm (San Jose, Calif.) can beengaged to provide human antibodies directed against a selected antigenusing technology similar to that described above.

A chimeric antibody is a molecule in which different portions of theantibody are derived from different immunoglobulin molecules such asantibodies having a variable region derived from a human antibody and anon-human immunoglobulin constant region. Methods for producing chimericantibodies are known in the art. See e.g., Morrison, 1985, Science229:1202; Oi et al., 1986, BioTechniques 4:214; Gillies et al., 1989, J.Immunol. Methods 125:191-202; and U.S. Pat. Nos. 5,807,715, 4,816,567,and 4,8 16397, which are incorporated herein by reference in theirentirety. Chimeric antibodies comprising one or more CDRs from humanspecies and framework regions from a non-human immunoglobulin moleculecan be produced using a variety of techniques known in the artincluding, for example, CDR-grafting (EP 239,400; PCT publication No. WO91/09967; and U.S. Pat. Nos. 5,225,539, 5,530,101, and 5,585,089),veneering or resurfacing (EP 592,106; EP 519,596; Padlan, 1991,Molecular Immunology 28(4/5):489-498; Studnicka et al., 1994, ProteinEngineering 7(6):805-814; and Roguska et al., 1994, PNAS 91:969-973),and chain shuffling (U.S. Pat. No. 5,565,332). In a preferredembodiment, chimeric antibodies comprise a human CDR3 having an aminoacid sequence of any one of the CDR3 listed in Table 2 and non-humanframework regions. Often, framework residues in the framework regionswill be substituted with the corresponding residue from the CDR donorantibody to alter, preferably improve, antigen binding. These frameworksubstitutions are identified by methods well known in the art, e.g., bymodeling of the interactions of the CDR and framework residues toidentify framework residues important for antigen binding and sequencecomparison to identify unusual framework residues at particularpositions. (See, e.g., Queen et al., U.S. Pat. No. 5,585,089; andRiechmann et al., 1988, Nature 332:323, which are incorporated herein byreference in their entireties.)

Further, the antibodies of the invention can, in turn, be utilized togenerate anti-idiotype antibodies that “mimic” RSV antigens usingtechniques well known to those skilled in the art. (See, e.g., Greenspan& Bona, 1989, FASEB J. 7(5):437-444; and Nissinoff, 1991, J. Immunol.147(8):2429-2438). For example, antibodies of the invention which bindto and competitively inhibit the binding of RSV (as determined by assayswell known in the art and disclosed in supra) to its host cell receptorcan be used to generate anti-idiotypes that “mimic” a RSV antigenbinding domain and, as a consequence, bind to and neutralize RSV and/orits host cell receptor. Such neutralizing anti-idiotypes or Fabfragments of such anti-idiotypes can be used in therapeutic regimens toneutralize RSV. For example, such anti-idiotypic antibodies can be usedto bind RSV and/or to bind its host cell receptors, and thereby blockinfection.

5.6.1. Polynucleotides Encoding an Antibody

The invention provides polynucleotides comprising a nucleotide sequenceencoding an antibody of the invention or a fragment thereof. Theinvention also encompasses polynucleotides that hybridize under highstringency, intermediate or lower stringency hybridization conditions,e.g., as defined supra, to polynucleotides that encode an antibody ofthe invention.

The polynucleotides may be obtained, and the nucleotide sequence of thepolynucleotides determined, by any method known in the art. Since theamino acid sequences of the antibodies are known (as described in Table2), nucleotide sequences encoding these antibodies can be determinedusing methods well known in the art, i.e., nucleotide codons known toencode particular amino acids are assembled in such a way to generate anucleic acid that encodes the antibody or fragment thereof of theinvention. Such a polynucleotide encoding the antibody may be assembledfrom chemically synthesized oligonucleotides (e.g., as described inKutmeier et al., 1994, BioTechniques 17:242), which, briefly, involvesthe synthesis of overlapping oligonucleotides containing portions of thesequence encoding the antibody, annealing and ligating of thoseoligonucleotides, and then amplification of the ligated oligonucleotidesby PCR.

Alternatively, a polynucleotide encoding an antibody may be generatedfrom nucleic acid from a suitable source. If a clone containing anucleic acid encoding a particular antibody is not available, but thesequence of the antibody molecule is known, a nucleic acid encoding theimmunoglobulin may be chemically synthesized or obtained from a suitablesource (e.g., an antibody cDNA library, or a cDNA library generatedfrom, or nucleic acid, preferably poly A+ RNA, isolated from, any tissueor cells expressing the antibody, such as hybridoma cells selected toexpress an antibody of the invention) by PCR amplification usingsynthetic primers hybridizable to the 3′ and 5′ ends of the sequence orby cloning using an oligonucleotide probe specific for the particulargene sequence to identify, e.g., a cDNA clone from a cDNA library thatencodes the antibody. Amplified nucleic acids generated by PCR may thenbe cloned into replicable cloning vectors using any method well known inthe art.

Once the nucleotide sequence of the antibody is determined, thenucleotide sequence of the antibody may be manipulated using methodswell known in the art for the manipulation of nucleotide sequences,e.g., recombinant DNA techniques, site directed mutagenesis, PCR, etc.(see, for example, the techniques described in Sambrook et al., 1990,Molecular Cloning, A Laboratory Manual, 2d Ed., Cold Spring HarborLaboratory, Cold Spring Harbor, N.Y. and Ausubel et al., eds., 1998,Current Protocols in Molecular Biology, John Wiley & Sons, NY, which areboth incorporated by reference herein in their entireties), to generateantibodies having a different amino acid sequence, for example to createamino acid substitutions, deletions, and/or insertions.

In a specific embodiment, one or more of the CDRs is inserted withinframework regions using routine recombinant DNA techniques. Theframework regions may be naturally occurring or consensus frameworkregions, and preferably human framework regions (see, e.g., Chothia etal., 1998, J. Mol. Biol. 278: 457-479 for a listing of human frameworkregions). Preferably, the polynucleotide generated by the combination ofthe framework regions and CDRs encodes an antibody that specificallybinds to a RSV antigen. Preferably, as discussed supra, one or moreamino acid substitutions may be made within the framework regions, and,preferably, the amino acid substitutions improve binding of the antibodyto its antigen. Additionally, such methods may be used to make aminoacid substitutions or deletions of one or more variable region cysteineresidues participating in an intrachain disulfide bond to generateantibody molecules lacking one or more intrachain disulfide bonds. Otheralterations to the polynucleotide are encompassed by the presentinvention and within the skill of the art.

5.6.2. Recombinant Expression of an Antibody

Recombinant expression of an antibody of the invention, derivative oranalog thereof, (e.g., a heavy or light chain of an antibody of theinvention or a portion thereof or a single chain antibody of theinvention), requires construction of an expression vector containing apolynucleotide that encodes the antibody. Once a polynucleotide encodingan antibody molecule or a heavy or light chain of an antibody, orportion thereof (preferably, but not necessarily, containing the heavyor light chain variable domain), of the invention has been obtained, thevector for the production of the antibody molecule may be produced byrecombinant DNA technology using techniques well known in the art. Thus,methods for preparing a protein by expressing a polynucleotidecontaining an antibody encoding nucleotide sequence are describedherein. Methods which are well known to those skilled in the art can beused to construct expression vectors containing antibody codingsequences and appropriate transcriptional and translational controlsignals. These methods include, for example, in vitro recombinant DNAtechniques, synthetic techniques, and in vivo genetic recombination. Theinvention, thus, provides replicable vectors comprising a nucleotidesequence encoding an antibody molecule of the invention, a heavy orlight chain of an antibody, a heavy or light chain variable domain of anantibody or a portion thereof, or a heavy or light chain CDR, operablylinked to a promoter. Such vectors may include the nucleotide sequenceencoding the constant region of the antibody molecule (see, e.g., PCTPublication WO 86/05807; PCT Publication WO 89/01036; and U.S. Pat. No.5,122,464) and the variable domain of the antibody may be cloned intosuch a vector for expression of the entire heavy, the entire lightchain, or both the entire heavy and light chains.

The expression vector is transferred to a host cell by conventionaltechniques and the transfected cells are then cultured by conventionaltechniques to produce an antibody of the invention. Thus, the inventionincludes host cells containing a polynucleotide encoding an antibody ofthe invention or fragments thereof, or a heavy or light chain thereof,or portion thereof, or a single chain antibody of the invention,operably linked to a heterologous promoter. In preferred embodiments forthe expression of double-chained antibodies, vectors encoding both theheavy and light chains may be co-expressed in the host cell forexpression of the entire immunoglobulin molecule, as detailed below.

A variety of host-expression vector systems may be utilized to expressthe antibody molecules of the invention (see, e.g., U.S. Pat. No.5,807,715). Such host-expression systems represent vehicles by which thecoding sequences of interest may be produced and subsequently purified,but also represent cells which may, when transformed or transfected withthe appropriate nucleotide coding sequences, express an antibodymolecule of the invention in situ. These include but are not limited tomicroorganisms such as bacteria (e.g., E. coli and B. subtilis)transformed with recombinant bacteriophage DNA, plasmid DNA or cosmidDNA expression vectors containing antibody coding sequences; yeast(e.g., Saccharomyces Pichia) transformed with recombinant yeastexpression vectors containing antibody coding sequences; insect cellsystems infected with recombinant virus expression vectors (e.g.,baculovirus) containing antibody coding sequences; plant cell systemsinfected with recombinant virus expression vectors (e.g., cauliflowermosaic virus, CaMV; tobacco mosaic virus, TMV) or transformed withrecombinant plasmid expression vectors (e.g., Ti plasmid) containingantibody coding sequences; or mammalian cell systems (e.g., COS, CHO,BHK, 293, NSO, and 3T3 cells) harboring recombinant expressionconstructs containing promoters derived from the genome of mammaliancells (e.g., metallothionein promoter) or from mammalian viruses (e.g.,the adenovirus late promoter; the vaccinia virus 7.5K promoter).Preferably, bacterial cells such as Escherichia coli, and morepreferably, eukaryotic cells, especially for the expression of wholerecombinant antibody molecule, are used for the expression of arecombinant antibody molecule. For example, mammalian cells such asChinese hamster ovary cells (CHO), in conjunction with a vector such asthe major intermediate early gene promoter element from humancytomegalovirus is an effective expression system for antibodies(Foecking et al., 1986, Gene 45:101; and Cockett et al., 1990,Bio/Technology 8:2). In a specific embodiment, the expression ofnucleotide sequences encoding antibodies or fragments thereof whichimmunospecifically bind to one or more RSV antigens is regulated by aconstitutive promoter, inducible promoter or tissue specific promoter.

In bacterial systems, a number of expression vectors may beadvantageously selected depending upon the use intended for the antibodymolecule being expressed. For example, when a large quantity of such aprotein is to be produced, for the generation of pharmaceuticalcompositions of an antibody molecule, vectors which direct theexpression of high levels of fusion protein products that are readilypurified may be desirable. Such vectors include, but are not limited to,the E. coli expression vector pUR278 (Ruther et al., 1983, EMBO12:1791), in which the antibody coding sequence may be ligatedindividually into the vector in frame with the lac Z coding region sothat a fusion protein is produced; pIN vectors (Inouye & Inouye, 1985,Nucleic Acids Res. 13:3101-3109; Van Heeke & Schuster, 1989, J. Biol.Chem. 24:5503-5509); and the like. pGEX vectors may also be used toexpress foreign polypeptides as fusion proteins with glutathione5-transferase (GST). In general, such fusion proteins are soluble andcan easily be purified from lysed cells by adsorption and binding tomatrix glutathione agarose beads followed by elution in the presence offree glutathione. The pGEX vectors are designed to include thrombin orfactor Xa protease cleavage sites so that the cloned target gene productcan be released from the GST moiety.

In an insect system, Autographa californica nuclear polyhedrosis virus(AcNPV) is used as a vector to express foreign genes. The virus grows inSpodoptera frugiperda cells. The antibody coding sequence may be clonedindividually into non-essential regions (for example the polyhedringene) of the virus and placed under control of an AcNPV promoter (forexample the polyhedrin promoter).

In mammalian host cells, a number of viral-based expression systems maybe utilized. In cases where an adenovirus is used as an expressionvector, the antibody coding sequence of interest may be ligated to anadenovirus transcription/translation control complex, e.g., the latepromoter and tripartite leader sequence. This chimeric gene may then beinserted in the adenovirus genome by in vitro or in vivo recombination.Insertion in a non-essential region of the viral genome (e.g., region E1or E3) will result in a recombinant virus that is viable and capable ofexpressing the antibody molecule in infected hosts (e.g., see Logan &Shenk, 1984, Proc. Natl. Acad. Sci. USA 8 1:355-359). Specificinitiation signals may also be required for efficient translation ofinserted antibody coding sequences. These signals include the ATGinitiation codon and adjacent sequences. Furthermore, the initiationcodon must be in phase with the reading frame of the desired codingsequence to ensure translation of the entire insert. These exogenoustranslational control signals and initiation codons can be of a varietyof origins, both natural and synthetic. The efficiency of expression maybe enhanced by the inclusion of appropriate transcription enhancerelements, transcription terminators, etc. (see, e.g., Bittner et al.,1987, Methods in Enzymol. 153:51-544).

In addition, a host cell strain may be chosen which modulates theexpression of the inserted sequences, or modifies and processes the geneproduct in the specific fashion desired. Such modifications (e.g.,glycosylation) and processing (e.g., cleavage) of protein products maybe important for the function of the protein. Different host cells havecharacteristic and specific mechanisms for the post-translationalprocessing and modification of proteins and gene products. Appropriatecell lines or host systems can be chosen to ensure the correctmodification and processing of the foreign protein expressed. To thisend, eukaryotic host cells which possess the cellular machinery forproper processing of the primary transcript, glycosylation, andphosphorylation of the gene product may be used. Such mammalian hostcells include but are not limited to CHO, VERY, BHK, Hela, COS, MDCK,293, 3T3, WI 38, BT483, Hs578T, HTB2, BT20 and T47D, NSO (a murinemyeloma cell line that does not endogenously produce any immunoglobulinchains), CRL7O3O and HsS78Bst cells.

For long-term, high-yield production of recombinant proteins, stableexpression is preferred. For example, cell lines which stably expressthe antibody molecule may be engineered. Rather than using expressionvectors which contain viral origins of replication, host cells can betransformed with DNA controlled by appropriate expression controlelements (e.g., promoter, enhancer, sequences, transcriptionterminators, polyadenylation sites, etc.), and a selectable marker.Following the introduction of the foreign DNA, engineered cells may beallowed to grow for 1-2 days in an enriched media, and then are switchedto a selective media. The selectable marker in the recombinant plasmidconfers resistance to the selection and allows cells to stably integratethe plasmid into their chromosomes and grow to form foci which in turncan be cloned and expanded into cell lines. This method mayadvantageously be used to engineer cell lines which express the antibodymolecule. Such engineered cell lines may be particularly useful inscreening and evaluation of compositions that interact directly orindirectly with the antibody molecule.

A number of selection systems may be used, including but not limited to,the herpes simplex virus thymidine kinase (Wigler et al., 1977, Cell11:223), hypoxanthineguanine phosphoribosyltransferase (Szybalska &Szybalski, 1992, Proc. Natl. Acad. Sci. USA 48:202), and adeninephosphoribosyltransferase (Lowy et al., 1980, Cell 22:8-17) genes can beemployed in tk-, hgprt- or aprt-cells, respectively. Also,antimetabolite resistance can be used as the basis of selection for thefollowing genes: dhfr, which confers resistance to methotrexate (Wigleret al., 1980, Natl. Acad. Sci. USA 77:357; O'Hare et al., 1981, Proc.Natl. Acad. Sci. USA 78:1527); gpt, which confers resistance tomycophenolic acid (Mulligan & Berg, 1981, Proc. Natl. Acad. Sci. USA78:2072); neo, which confers resistance to the aminoglycoside G-418 (Wuand Wu, 1991, Biotherapy 3:87-95; Tolstoshev, 1993, Ann. Rev. Pharmacol.Toxicol. 32:573-596; Mulligan, 1993, Science 260:926-932; and Morgan andAnderson, 1993, Ann. Rev. Biochem. 62: 191-217; May, 1993, TIB TECH11(5):155-2 15); and hygro, which confers resistance to hygromycin(Santerre et al., 1984, Gene 30:147). Methods commonly known in the artof recombinant DNA technology may be routinely applied to select thedesired recombinant clone, and such methods are described, for example,in Ausubel et al. (eds.), Current Protocols in Molecular Biology, JohnWiley & Sons, NY (1993); Kriegler, Gene Transfer and Expression, ALaboratory Manual, Stockton Press, NY (1990); and in Chapters 12 and 13,Dracopoli et al. (eds), Current Protocols in Human Genetics, John Wiley& Sons, NY (1994); Colberre-Garapin et al., 1981, J. Mol. Biol. 150:1,which are incorporated by reference herein in their entireties.

The expression levels of an antibody molecule can be increased by vectoramplification (for a review, see Bebbington and Hentschel, The use ofvectors based on gene amplification for the expression of cloned genesin mammnalian cells in DNA cloning, Vol.3. (Academic Press, New York,1987)). When a marker in the vector system expressing antibody isamplifiable, increase in the level of inhibitor present in culture ofhost cell will increase the number of copies of the marker gene. Sincethe amplified region is associated with the antibody gene, production ofthe antibody will also increase (Crouse et al., 1983, Mol. Cell. Biol.3:257).

The host cell may be co-transfected with two expression vectors of theinvention, the first vector encoding a heavy chain derived polypeptideand the second vector encoding a light chain derived polypeptide. Thetwo vectors may contain identical selectable markers which enable equalexpression of heavy and light chain polypeptides. Alternatively, asingle vector may be used which encodes, and is capable of expressing,both heavy and light chain polypeptides. In such situations, the lightchain should be placed before the heavy chain to avoid an excess oftoxic free heavy chain (Proudfoot, 1986, Nature 322:52; and Kohler,1980, Proc. Natl. Acad. Sci. USA 77:2 197). The coding sequences for theheavy and light chains may comprise cDNA or genomic DNA.

Once an antibody molecule of the invention has been produced byrecombinant expression, it may be purified by any method known in theart for purification of an immunoglobulin molecule, for example, bychromatography (e.g., ion exchange, affinity, particularly by affinityfor the specific antigen after Protein A, and sizing columnchromatography), centrifugation, differential solubility, or by anyother standard technique for the purification of proteins. Further, theantibodies of the present invention or fragments thereof may be fused toheterologous polypeptide sequences described herein or otherwise knownin the art to facilitate purification.

5.7. Kits

The invention also provides a pharmaceutical pack or kit comprising oneor more containers filled with one or more of the ingredients of thepharmaceutical compositions of the invention. Optionally associated withsuch container(s) can be a notice in the form prescribed by agovernmental agency regulating the manufacture, use or sale ofpharmaceuticals or biological products, which notice reflects approvalby the agency of manufacture, use or sale for human administration.

The present invention provides kits that can be used in the abovemethods. In one embodiment, a kit comprises an antibody of theinvention, preferably a purified antibody, in one or more containers. Inan alterative embodiment, a kit comprises an antibody fragment thatimmunospecifically binds to a RSV antigen. In a specific embodiment, thekits of the present invention contain a substantially isolated RSVantigen as a control. Preferably, the kits of the present inventionfurther comprise a control antibody which does not react with the RSVantigen. In another specific embodiment, the kits of the presentinvention contain a means for detecting the binding of an antibody to aRSV antigen (e.g., the antibody may be conjugated to a detectablesubstrate such as a fluorescent compound, an enzymatic substrate, aradioactive compound or a luminescent compound, or a second antibodywhich recognizes the first antibody may be conjugated to a detectablesubstrate). In specific embodiments, the kit may include a recombinantlyproduced or chemically synthesized RSV antigen. The RSV antigen providedin the kit may also be attached to a solid support. In a more specificembodiment the detecting means of the above-described kit includes asolid support to which RSV antigen is attached. Such a kit may alsoinclude a non-attached reporter-labeled anti-human antibody. In thisembodiment, binding of the antibody to the RSV antigen can be detectedby binding of the said reporter-labeled antibody.

In an additional embodiment, the invention includes a diagnostic kit foruse in screening serum containing RSV antigens. The diagnostic kitincludes a substantially isolated antibody specifically immunoreactivewith a RSV antigen, and means for detecting the binding of the RSVantigen to the antibody. In one embodiment, the antibody is attached toa solid support. In a specific embodiment, the antibody may be amonoclonal antibody. The detecting means of the kit may include asecond, labeled monoclonal antibody. Alternatively, or in addition, thedetecting means may include a labeled, competing antigen.

In one diagnostic configuration, test serum is reacted with a solidphase reagent having a surface-bound RSV antigen obtained by the methodsof the present invention. After the RSV antigen binds to a specificantibody, the unbound serum components are removed by washing,reporter-labeled anti-human antibody is added, unbound anti-humanantibody is removed by washing, and a reagent is reacted withreporter-labeled anti-human antibody to bind reporter to the reagent inproportion to the amount of bound anti-RSV antigen antibody on the solidsupport. Typically, the reporter is an enzyme which is detected byincubating the solid phase in the presence of a suitable fluorometric,luminescent or calorimetric substrate (Sigma, St. Louis, Mo.).

The solid surface reagent in the above assay is prepared by knowntechniques for attaching protein material to solid support material,such as polymeric beads, dip sticks, 96-well plate or filter material.These attachment methods generally include non-specific adsorption ofthe protein to the support or covalent attachment of the protein,typically through a free amine group, to a chemically reactive group onthe solid support, such as an activated carboxyl, hydroxyl, or aldehydegroup. Alternatively, streptavidin coated plates can be used inconjunction with biotinylated antigen(s).

Thus, the invention provides an assay system or kit for carrying outthis diagnostic method. The kit generally includes a support withsurface-bound recombinant RSV antigen, and a reporter-labeled anti-humanantibody for detecting surface-bound anti-RSV antigen antibody.

6. EXAMPLE Kinetic Analysis of Humanized RSV Mabs by BIACORE™

A typical kinetic study involved the injection of 250 μl of monoclonalantibody (“Mab”) at varying concentrations (25-300 nM) in PBS buffercontaining 0.05% Tween-20 (PBS/Tween). The flow rate was maintained at75 μl/min, giving a 15 minute dissociation time. Following the injectionof Mab, the flow was exchanged with PBS/Tween buffer for 30 min fordetermining the rate of dissociation. The sensor chip was regeneratedbetween cycles with a 1 min pulse of 100 mM HCl. The regeneration stepcaused a minimal loss of binding capacity of the immobilized F-protein(4% loss per cycle). This small decrease did not change the calculatedvalues of the rate constants for binding and dissociation (also calledthe k_(on) and k_(off), respectively).

More specifically, for measurement of k_(assoc) (or k_(on)), F proteinwas directly immobilized by the EDC/NHS method(EDC=N-ethyl-N′-[3-diethylaminopropyl)-carbodiimide). Briefly, 25 mg/mlof F protein in 10 mM NaoAc, pH 5.0 was prepared and about a 5-10 μlinjection gives about 30-50 RU (response units) of immobilized F proteinunder the above referenced conditions. The blank was subtracted forkinetic analysis. The column could be regenerated using 100 mM HCl (with60 seconds of contact time being required for full regeneration). Thistreatment removed bound Fab completely without damaging the immobilizedantigen and could be used for over 40 regenerations. For k_(on)measurements, Fab concentrations were 0.39 nM, 0.75 nM, 1.56 nM, 3.13nM, 12.5 nM, 25 nM, 50 nM, and 100 nM. The dissociation phase wasanalyzed for approximately 900 seconds. Kinetics were analyzed by 1:1Langmuir fitting (global fitting). Measurements were done in HBS-EPbuffer (10 mM HEPES, pH 7.4, 150 mM NaCl, 3 mM EDTA, 0.005% (v/v)Surfactant P20.

For measurements of combinatorial clones, as disclosed herein, thek_(on) and k_(off) were measured separately. The k_(on) was measured atconditions that were the same as those for the single mutation clonesand was analyzed similarly.

For measuring k_(off), the following conditions were employed. Briefly,4100 RU of F protein were immobilized (as above) with CM-dextran used asthe blank. Here, 3000 RU of Fab was bound (with dissociated Fab highenough to offset machine fluctuation). HBS plus 5 nM F protein (about350-2000 times higher than the K_(d)—the dissociation equilibriumconstant) was used as buffer. The dissociation phase was 6-15 hours at aflow rate of 5 ml/min. Under the conditions used herein, re-binding ofthe dissociated Fab was minimal. For further details, see the manualwith the biosensor.

The binding of the high affinity anti-RSV antibodies to the F protein,or other epitopic sites on RSV, disclosed herein was calculated from theratio of the first order rate constant for dissociation to the secondorder rate constant for binding or association (K_(d)=k_(off)/k_(on)).The value for k_(on) was calculated based on the following rateequation:dR/dt=k _(on) [Mab]R _(max)−(k _(on) [Mab]+k _(off))Rwhere R and R_(max) are the response units at time t and infinity,respectively. A plot of dr/dt as a function of R gives a slope of (k_(a)[Mab]+k_(d))—since these slopes are linearly related to the [Mab], thevalue k_(on) can be derived from a replot of the slopes versus [Mab].The slope of the new line is equal to k_(on). Although the value ofk_(off) can be extrapolated from the Y-intercept, a more accurate valuewas determined by direct measurement of k_(off). Following the injectionphase of the Mab, PBS/Tween buffer flows across the sensor chip. Fromthis point, [Mab]=0. The above stated equation for dR/dt thus reducesto:dr/dt=k or dR/R=k _(off) dtIntegration of this equation then gives:ln(R ₀ /R _(t))=k _(off) twhere R₀/R_(t)) are the response units at time 0 (start of dissociationphase) and t, respectively. Lastly, plotting In(R₀/R_(t)) as a functionof t gives a slope of k_(off).

The numerical values from such antibody variants were as shown in Tables4-7 below.

TABLE 4 Summary of Kinetic Constants for High Potency Antibodies.ANTIBODY K_(on) × 10⁵ (M⁻¹s⁻¹) K_(off) × 10⁻⁴ (s⁻¹) EC₅₀ (nM)**SYNAGIS ® 2.04; 1.89; 2.18 7.64; 7.38; 7.02 3.57 **AFFF 1.08; 0.96;1.24 2.74; 2.66; 2.06 *1X-493L1FR 1.85 6.5 *H3-3F4 4.59; 4.67; 5.72;4.45; 4.02 6.25; 5.33 *M3H9 6.05 3.38 *Y10H6 7.57 4.62 *DG 2.65; 2.83;4.16; 1.67; 4.44 3.18; 2.88 *AFFF 2.12; 1.56; 1.86 2.45; 4.46; 2.68 *6H83.14; 4.44 1.78; 4.73 *L1-7E5 3.29; 3.57; 4.05; 1.92; 3.31; 2.29 3.35;4.26 *L2-15B10 3.69; 2.82; 3.12; 1.34; 4.16; 2.70 5.33; 3.78 *P12f2 6.632.82 0.65 *P12f4 5.27 2.99 0.70 *P11d4 5.70; 5.72 7.17 >20 *Ale9 7.94.53 2.5 *A12a6 7.43 2.30 0.62 *A13a11 7.35 2.50 2.04 *A13c4 7.81; 7.352.80 0.52

TABLE 5 Monoclonal Antibodies vs Bac-F (1:1) K_(on) (×E + 5) K_(off) (×E− 5) K_(D) (nM) Chi2 P12f2 4.07 12.8 0.31 (13) 0.9 P12f4 4.95 5.55 0.11(35) 0.6 A13c4 3.00 3.96 0.13 (30) 1.2 A12a6 4.60 1.65 0.04 (98) 1.2A1e9 4.33 14.3 0.33 (12) 2.5 A8c7 4.17 8.75 0.21 (19) 1.8 P11d4 4.6628.9 0.62 (6) 1.0 A17d4 4.56 4.07 0.09 (43) 0.5 A4B4 4.34 1.06 0.02(195) 1.5 SYNAGIS ® 1.32 51.5 3.90 (1) 0.6

TABLE 6 Monoclonal Antibodies vs NUF4 (1:1) K_(on) (×E + 5) K_(off) (×E− 5) K_(D) (nM) Chi2 P12f2 5.41 17.8 0.33 (26) 1.2 P12f4 9.43 22.9 0.24(36) 0.9 A13c4 3.65 27.2 0.75 (12) 1.8 A12a6 4.00 29.1 0.73 (12) 1.9A1e9 8.43 58.4 0.69 (13) 0.9 A8c7 8.25 53.5 0.65 (13) 0.7 P11d4 9.0476.6 0.85 (10) 2.5 A17d4 4.99 36.2 0.73 (12) 2.0 A4B4 4.96 28.2 0.57(15) 1.9 SYNAGIS ® 3.04 265 8.70 (1) 0.4

TABLE 7 Monoclonal Antibodies vs NUF4 (2:1) K_(n) (×E + 5) K_(off) (×E −5) K_(D) (nM) Chi2 P12f2 2.82 23.6 0.84 (371) 1.5 P12f4 2.73 63.6 2.33(134) 4.9 A13c4 3.20 22.5 0.70 (446) 1.7 A12a6 2.18 40.8 1.87 (167) 1.9A1e9 3.29 139 4.22 (74) 2.8 A8c7 4.30 114 2.65 (118) 2.0 P11d4 3.66 3138.55 (36) 3.6 A17d4 2.64 29.2 1.11 (281) 1.7 A4B4 2.03 40.06 2.00 (156)1.4 SYNAGIS ® 0.78 2420  312 (1) 1.3

1X-493L2FR, H3-3F4, M3H9, Y10H6, DG, AFFF, 6H8, L1-7E5, L2-15B10, P12F2,P12F4, P11d4, A1e9, A12a6, A13a11, and A13c4 are Fab fragments havingthe framework sequences of FIG. 2 and the CDR sequences indicated listedin Table 2. SYNAGIS® is a monoclonal antibody with the frameworksequences of FIG. 1 and constant regions as described in Johnson et al.(1997, Journal of Infectious Diseases 176:1215-1224) and U.S. Pat. No.5,824,307. The framework sequences of the this antibody may differslightly from those of the Fab fragments.

The amino acid sequences of the indicated CDRs in Table 1 represent theamino acid residues located at the key locations within the CDRs of thehigh potency antibodies produced by the methods described herein and incopending applications Ser. Nos. 60/168,426 and 60/186,252. For example,to increase the potency of an antibody by producing a higher k_(on)value, the amino acids located at the key positions as taught herein bythe bold and underlined residues in Table 1 for the reference antibodywould be replaced by the amino acids listed under CDRs in Table 2 (andalso bold and underlined). Thus, these one letter codes represent theamino acids replacing the reference amino acids at the key positions (orcritical positions) of the CDRs shown in FIG. 2 (residues in bold in thesequences of Table 2) for a reference antibody whose potency is to beincreased.

7. EXAMPLE Microneutralization Assay

Neutralization of the antibodies of the present invention weredetermined by microneutralization assay. This microneutralization assayis a modification of the procedures described by Anderson et al. (1985,J. Clin. Microbiol. 22:1050-1052, the disclosure of which is herebyincorporated by reference in its entirety). The procedure used here isdescribed in Johnson et al., 1999, J. Infectious Diseases 180:35-40, thedisclosure of which is hereby incorporated by reference in its entirety.Antibody dilutions were made in triplicate using a 96-well plate. TenTCID₅₀ of respiratory syncytial virus (RSV—Long strain) were incubatedwith serial dilutions of the antibody (or Fabs) to be tested for 2 hoursat 37° C. in the wells of a 96-well plate. RSV susceptible HEp-2 cells(2.5×10⁴) were then added to each well and cultured for 5 days at 37° C.in 5% CO₂. After 5 days, the medium was aspirated and cells were washedand fixed to the plates with 80% methanol and 20% PBS. RSV replicationwas then determined by F protein expression. Fixed cells were incubatedwith a biotin-conjugated anti-F protein monoclonal antibody (pan Fprotein, C-site-specific MAb 133-1H) washed and horseradish peroxidaseconjugated avidin was added to the wells. The wells were washed againand turnover of substrate TMB (thionitrobenzoic acid) was measured at450 nm. The neutralizing titer was expressed as the antibodyconcentration that caused at least 50% reduction in absorbency at 450 nm(the OD₄₅₀) from virus-only control cells. The results from the assayfor the monoclonal antibodies and Fab fragments listed in Table 2 areshown in Table 4 supra and Table 8 infra.

TABLE 8 End Point RSV Microneutralization Titer Of High On Rate MutantIgG and Fab Mean Fold Mean Fold IC50 STDEV Difference IC50 STDEVDifference (Curve) Curve (Curve (Control) Control (Control n (assayMolecule μg/ml IC50 ICX50) μg/ml IC50 IC50) repeat) **SYNAGIS ® 0.45270.208 — 0.5351 0.238 — 8 **A1e9 0.0625 0.0268 7 0.0645 0.0223 8 3**A17d4 0.0342 0.022 13 0.0354 0.0187 15 4 **P11d4 0.0217 0.0331 210.0289 0.0110 19 5 **P12f2 0.0231 0.0141 20 0.0223 0.0083 24 6 **A8c70.0337 0.0309 13 0.0383 0.0283 14 5 **A12a6 0.0357 0.0316 13 0.03540.0261 15 7 **P12f4 0.0242 0.0163 19 0.0235 0.0076 23 7 **A13c4 0.03760.0268 12 0.0375 0.0213 14 6 **A4B4 0.0171 0.0018 27 0.0154 0.00417 35 2*A1e9 0.157 — 3 0.125 — 4 1 *A17d4 0.0179 — 25 0.0171 — 31 1*P11d4 >1.00 — — >1.00 — — 1 *P12f2 0.0407 0.0112 11 0.0326 0.00905 16 2*A8c7 0.177 — 3 0.157 — 34 1 *A12a6 0.0287 0.00417 16 0.0310 0.00982 172 *P12f4 0.0464 0.00791 10 0.0351 0.0126 15 2 *A13c4 0.0264 0.00141 170.0258 0.00071 21 2 *A4B4 0.0414 — 11 0.0411 — 13 1 *A13a11 0.120 0.02224 0.1022 0.0260 5 2 *A1h5 0.194 0.462 2 0.176 0.0625 3 2 **MonoclonalAntibody *Fab Fragment

8. EXAMPLE RSV Fusion Inhibition Assay

The ability of the antibodies of the invention or fragments thereof toblock RSV-induced fusion after viral attachment to the cells isdetermined in a fusion inhibition assay. This assay is identical to themicroneutralization assay, except that the cells were infected with RSV(Long) for four hours prior to addition of antibody (Taylor et al, 1992,J. Gen. Virol. 73:2217-2223).

9. EXAMPLE Isothermal Titration Calorimetry

Thermodynamic binding affinities and enthalpies were determined fromisothermal titration calorimetry (ITC) measurements on the interactionof antibodies with RSV F glycoprotein (NUF4), an antigen which mimicsthe binding site of the RSV virus.

Methods & Materials

Antibodies & Antigen

A13c4, A17d4, A4B4, and SYNAGIS® were diluted in dialysate and theconcentrations were determined by UV spectroscopic absorptionmeasurements with a Perkin-Elmer Lambda 4B Spectrophotometer using anextinction coefficient of 217,000 M⁻¹ cm² at the peak maximum at 280 nm.The diluted NUF4 concentrations were calculated from the ratio of themass of the original sample to that of the diluted sample since itsextinction coefficient was too low to determine an accurateconcentration without employing and losing a large amount of sample.

ITC Measurements

The binding thermodynamics of the antibodies were determined from ITCmeasurements using a Microcal, Inc. VP Titration Calorimeter. The VPtitration calorimeter consists of a matched pair of sample and referencevessels (1.409 ml) enclosed in an adiabatic enclosure and a rotatingstirrer-syringe for titrating ligand solutions into the sample vessel.The ITC measurements were performed at 25° C. and 35° C. The samplevessel contained the antibody in the phosphate buffer while thereference vessel contained just the buffer solution. The phosphatebuffer solution was saline 67 mM PO₄ at pH 7.4 from HyClone, Inc. Fiveor ten μl aliquots of the 0.05 to 0.1 mM NUF4 solution were titrated 3to 4 minutes apart into the antibody sample solution until the bindingwas saturated as evident by the lack of a heat exchange signal. Withsome antibody sample solutions, additional constant amounts of heat withthe addition of each aliquot were observed following binding saturationof the antibody. This was attributed to a heat of dilution of the NUF4titrant and was subtracted from the titrant heats obtained during thetitration prior to analysis of the data.

A non-linear, least square minimization software program from Microcal,Inc., Origin 5.0, was used to fit the incremental heat of the ithtitration (ΔQ(i)) of the total heat, Q_(t), to the total titrantconcentration, X_(t), according to the following equations. (I),Q _(t) =nC _(t) ΔH _(b) *V{1+X _(t) /nC _(t)+1/nK _(b) C _(t)−[(1+X _(t)/nC _(t)+1/nK _(b) C _(t))²−4X _(t) /nC _(t)]^(1/2)}/2  (1a)ΔQ(i)=Q(i)+dVi/2V {Q(i)+Q(i−1)}−Q(i−1)  (1b)where C_(t) is the initial antibody concentration in the sample vessel,V is the volume of the sample vessel, and n is the stoichiometry of thebinding reaction, to yield values of K_(b), ΔH_(b)*, and n. The optimumrange of sample concentrations for the determination of K_(b) depends onthe value of K_(b) and is defined by the following relationship.C_(t)K_(b)n≦500  (2)so that at 1 μM the maximum Kb that can be determined is less than2.5×10⁸ M⁻¹. If the first titrant addition did not fit the bindingisotherm, it was neglected in the final analysis since it may reflectrelease of an air bubble at the syringe opening-solution interface.

Results

The ITC results are summarized in Table 9. The higher than 2stoichiometries in Table 9 indicate that either the concentrationdetermination of the antibody or NUF4 was incorrect. Since the same NUF4sample was used as a titrant with antibodies having the amino acidsequence of A13c4 at 35° C. and A17d4 at 35° C., which exhibit in atleast one of the titrations the correct stoichiometry of 2, it isassumed that the titrant concentration was correct and that the largevalues of n result from incorrectly determined antibody concentrations.However, it can be shown that the binding constants are criticallydependent on the titrant concentration and, thus, despite the 2-3disparity in n, the binding constants are correct. Since the bindingconstants of antibodies having the amino acid sequence of A4B4 and A13c4at 25° C. were near the upper determination limit by ITC (equation 2)and with the limited amount of available NUF4, it was decided to use 35°C. as the reference temperature for comprising the binding affinities.The results summarized in Table 9 show that the binding affinities toNUF4 are in the order A4B4<A13c4<A17d4<SYNAGIS®.

TABLE 9 Average Binding Constants and Enthalpies of NUF4 to AntibodiesAntibody K_(b) ΔH_(b) in kJ mol⁻¹ A4B4 269 ± 74 × 10⁶ M⁻¹ or ~3.7 nM*92.8 ± 1.0  A13c4 107 ± 28 × 10⁶ M⁻¹ or 9 nM 67 ± 17 A17d4 75 ± 14 × 10⁶M⁻¹ or 13 nM 68 ± 10 SYNAGIS ® 1.23 ± 0.17 × 10⁶ M⁻¹ or 810 nM 71 ± 5 *Based only on the best titration run at 35° C.4.0 nM is ITC lower limit of 1/K_(b) range (ITC range is limited to[antibody]_(n) K_(b)=500 where n is the stoichiometry and [antibody] isthe concentration of the antibody in the cell).

10. EXAMPLE Cotton Rat Prophylaxis

To determine the ability of SYNAGIS® to prevent lower respiratory tractRSV infection in cotton rats when administered by and intravenous (IV)route and to correlate the serum concentration of SYNAGIS® with areduction in lung RSV titer.

Materials & Methods

SYNAGIS® lot L94H048 was used for studies 111-47 and III-47A. SYNAGIS®lot L95 K016 was used for study III-58. Bovine serum albumin (BSA)(fraction V, Sigma Chemicals). RSV-Long (A subtype) was propagated inHep-2 cells.

On day 0, to groups of cotton rats (Sigmodon hispidis, average weight100 g) were administered SYNAGIS®, RSV-IGIV or BSA was administered byintramuscular injection. Twenty-four hours post administration, theanimals were bled and infected intranasally with 10⁵ pfu of RSV.Twenty-four hours later, the animals were bled and infected intranasallywith 10⁵ PFU or RSV (Long Strain). Four days after the infection,animals were sacrificed, and their lung tissue was harvested andpulmonary virus titers were determined by plaque titration. For studiesIII-47 and III-47A, the doses of monoclonal antibody (“MAb”) consistedof 0.31, 0.63, 1.25, 2.5, 5.5 and 10 mg/kg (body weight). For studiesIII-58, the doses of MAb consisted of 0.63, 1.25, 2.5, 5.5 and 10 mg/kg(body weight). In all three studies bovine serum albumin (BSA) 10 mg/kgwas used as a negative control. Human antibody concentrations in theserum at the time of challenge are determined using a sandwich ELISA.

Results

The results of the individual experiments are presented in Tables 10-12.The results of all of the experiments combined is shown in Table 13. Allthree studies show a significant reduction of pulmonary virus titers inanimals treated with SYNAGIS®. A clear dose-response effect was observedin the animals. The combined data indicated that a dose of 2.5 mg/kgresults in a greater than 99% reduction in lung RSV titer. The meanserum concentration of SYNAGIS® for this dose at the time of viralchallenge was 28.6 μg/ml.

TABLE 10 EXPERIMENT III-47 Lung Viral Mean ± Std Titer Error GeometricNumber Concentration Mean ± Std of of Human Error Compound Animals DoseIgG (μg/ml) (log10 pfu/gm) BSA 4 0 1.4 × 10⁵ ± 1.7 SYNAGIS ® 3 0.312mg/kg 3.83 ± 1.1  2.1 × 10⁴ ± 2.1 SYNAGIS ® 3 0.625 mg/kg 5.27 ± 0.377.7 × 10⁴ ± 1.6 SYNAGIS ® 4  1.25 mg/kg 9.15 ± 0.16 3.4 × 10⁴ ± 1.3SYNAGIS ® 3  2.50 mg/kg 23.4 ± 2.8  1.4 × 10³ ± 1.7 SYNAGIS ® 2  5.0mg/kg 42.4 ± 13.4 4.6 × 10² ± 4.6 SYNAGIS ® 4  10.0 mg/kg 141.1 ± 14.4 1.0 × 10² ± 1.0

TABLE 11 EXPERIMENT III-47A Lung Viral Mean ± Std Titer Error GeometricNumber Concentration Mean ± Std of of Human Error Compound Animals DoseIgG (μg/ml) (log10 pfu/gm) BSA 4 0 1.9 × 10⁵ ± 1.2 SYNAGIS ® 4 0.312mg/kg  1.8 ± 0.12 8.5 × 10⁴ ± 1.2 SYNAGIS ® 4 0.625 mg/kg  4.0 ± 0.195.0 × 10⁴ ± 1.6 SYNAGIS ® 4  1.25 mg/kg 11.8 ± 0.68 1.9 × 10³ ± 1.4SYNAGIS ® 4  2.50 mg/kg 18.9 ± 2.0  5.3 × 10³ ± 1.6 SYNAGIS ® 3  5.0mg/kg 55.6 ± 2.3  1.6 × 10² ± 1.3 SYNAGIS ® 4  10.0 mg/kg 109.7 ± 5.22 1.0 × 10² ± 1.0

TABLE 12 EXPERIMENT III-58 Lung Viral Mean ± Std Titer Error GeometricNumber Concentration Mean ± Std of of Human Error Compound Animals DoseIgG (μg/ml) (log10 pfu/gm) BSA 4 0 1.1 × 10⁵ ± 1.2 SYNAGIS ® 4 0.625mg/kg 5.78 ± 0.32 1.6 × 10⁴ ± 1.2 SYNAGIS ® 4  1.25 mg/kg 9.82 ± 0.231.6 × 10³ ± 1.3 SYNAGIS ® 4  2.50 mg/kg 34.1 ± 2.11 4.3 × 10² ± 1.6SYNAGIS ® 3  5.0 mg/kg 58.3 ± 4.48 1.0 × 10² ± 1.0 SYNAGIS ® 4  10.0mg/kg 111.5 ± 5.04  1.0 × 10² ± 1.0

TABLE 13 III-47, III-47A and III-58 COMBINED Lung Viral Titer Mean ± StdError Geometric Mean ± Std Number of Concentration of Error CompoundAnimals Dose Human IgG (μg/ml) (log10 pfu/gm) BSA 18 0 1.3 × 10⁵ ± 1.2SYNAGIS ®  7 0.312 mg/kg 2.67 ± 0.60 4.6 × 10⁴ ± 1.5 SYNAGIS ® 17 0.625mg/kg 5.27 ± 0.27 2.7 × 10⁴ ± 1.3 SYNAGIS ® 18  1.25 mg/kg 10.1 ± 0.293.3 × 10³ ± 1.4 SYNAGIS ® 17  2.50 mg/kg 28.6 ± 2.15 9.6 × 10² ± 1.5SYNAGIS ® 15  5.0 mg/kg 55.6 ± 3.43 1.3 × 10² ± 1.2 SYNAGIS ® 18  10.0mg/kg 117.6 ± 5.09  1.0 × 10² ± 1.0

11. EXAMPLE Intramuscular Cotton Rat Studies

This experiment demonstrates that a greater reduction in RSV titer isachieved when A4b4, A4b4-F52S or A4b4/L1FR-S28R is administeredintramuscularly to a cotton rat than when the same concentration ofSYNAGIS® is administered intramuscularly to a cotton rat.

Materials & Methods

Intramuscular Cotton Rat Prophylaxis

Cotton rats (S. hispidus, average weight 100 grams) were anesthetizedwith methoxyflurane and dosed with 0.1 ml of purified monoclonalantibody (MAb) or BSA control by intramuscular (i.m.) injection.Twenty-four hours later animals were again anesthetized, bled for serumMAb concentration determination, and challenged with 10⁵ PFU RSV long byintranasal (i.n.) instillation. Four days later animals were sacrificed,serum samples were obtained, and their lungs were harvested. Lungs werehomogenized in 10 parts (wt/vol) of Hanks Balanced Salt solution and theresultant suspension was used to determine pulmonary viral titers byplaque assay.

Intramuscular Cotton Rat Pharmacokinetics

Cotton rats (S. hispidus, average weight 100 grams) were anesthetizedwith methoxyflurane and dosed with 0.1 ml of purified MAb or BSA controlby intramuscular (i.m) injection. Twenty-four hours later all of theanimals were bled for serum MAb concentration determination, and half ofthe animals from each group were sacrificed to perform bronchoalveolarlavage (BAL). Four days later the remaining animals were sacrificed,serum samples were obtained and BAL performed.

Results

As shown in Tables 14-16, a greater reduction in RSV titer is achievedwith equivalent or lower lung levels of A4b4, A4b4-F52S, orA4b4/L1FR-S28R as with SYNAGIS®.

TABLE 14 Intramuscular Cotton Rat Prophylaxis Data 0.5 mg/kg 0.125 mg/kgSerum Lung log Serum Lung log IgG IgG Virus Titer Virus IgG IgG VirusTiter Virus (μg/ml) (μg/ml) (pfu/gm) Titer (μg/ml) (μg/ml) (pfu/gm)Titer Synagis 3.4 0.099 7.3 × 10³ 3.9 0.893 0.024 3.1 × 10⁴ 4.5A4b4-F52S 2.9 0.089 7.3 × 10² 2.9 0.781 0.020 8.6 × 10³ 3.9A4b4/L1FR-S28R 3.3 0.093 6.1 × 10² 2.8 0.748 0.016 2.3 × 10⁴ 4.4 BSA 5.9× 10⁴ 4.8

TABLE 15 Intramuscular Cotton Rat Prophylaxis Data 0.5 mg/kg 1 mg/kgSerum IgG Lung IgG log(10) Serum IgG Lung IgG log(10) Molecule μg/mlμg/ml Lung Virus μg/ml μg/ml Lung Virus A4b4 2.4 0.013 4.3 3.1 0.094 3.4Synagis 1.9 0.038 4.4 4.2 0.212 3.3 BSA 4.4

TABLE 16 Intramuscular Cotton Rat Pharmacokinetics Data 24 Hours 96hours Serum IgG BAL IgG Serum IgG BAL IgG Molecule (μg/ml) (ng/ml)(μg/ml) (ng/ml) A4b4 3.4 2.2 2.6 1.4 Synagis 4.1 5.3 2.8 3.5

12. EXAMPLE In Vitro Isolation of SYNAGIS® Specific Monoclonal AntibodyResistant Mutants(MARM) of RSV Strain A/Long

This example demonstrates that MARMs can be isolated from RSV laboratorystrain A/Long upon multiple rounds of selection in the presence ofSYNAGIS®.

Materials

SYNAGIS® (formulated product: ref RN1002.148), Control Pan RSV MAb Pool(Chemicon MAB858-4, a blend of three MAbs anti-F, G, and N proteins),anti-RSV Type A MAb (Chemicon MAB858-1), and anti-RSV Type B MAb(Chemicon MAB858-2) were used in this study. Secondary detectingreagents were either Alexa™488 conjugated Goat F(ab′)₂ anti-Mouse orHuman IgG (H+L). RSV A/Long strain (5×10⁷ TCID₅₀ ml) was propagated fromMaster Virus Bank 031797. HEp-2 cells were propagated in EMEMsupplemented with 10% FBS and 2 mM L-Gln in a 37° C., 5% CO₂environment. Total cellular RNAs were isolated from infected HEp-2 cellswith the Promega RNAgents Kit. cDNAs were synthesized with theBoehringer Mannheim 1^(st) Strand cDNA Synthesis Kit, using Oligo-(dT)primer. Amplification of a fragment of the F protein for DNA sequencingwas performed by Polymerase Chain Reaction (PCR), using gene-specificoligonucleotides (MR-120 and MR-122) and the Boehringer Mannheim HighFidelity PCR Kit.

Methods

Selection of MARMs:

4×10⁵ HEp-2 cells were seeded per well of a 24-well plate in growthmedium (EMEM, 10% FBS, 2 mM L-Gln) and incubated overnight in growthconditions (37° C., 5% CO₂). 40 wells were seeded for individual MARMselection. Prior to infection, a fresh vial of master virus bank RSVA/Long was thawed rapidly at 37° C. and the virus titer adjusted to4×10⁶ pfu/ml in HEp-2 growth medium. SYNAGIS® was added to the virusinoculum at a final concentration of 30 μg/ml, and the mixture wasincubated at 37° C. for one hour. An aliquot of RSV was incubated withan irrelevant Human IgG1 Mab (MEDI-507) and was used as a negativecontrol. An uninfected control well was also set up for each plate.Cells were washed once with fresh medium and were overlayed with 100 μlof RSV A/Long virus stock/MAb mixture (multiplicity of infection[m.o.i.]=4). Cells were incubated for four hours in growth conditionsfollowed by addition of 1 ml of growth medium to each well. Cytopathiceffect (CPE) was monitored on a daily basis by light microscopy.Following seven days of selection the contents of each well weresupplemented with a further 30 μg/ml of SYNAGIS® or irrelevant HumanIgG1 Mab, and were used to infect freshly seeded HEp-2 cells (4×10⁵cells/well of 24-well plate). After a further seven days of selectionthe process was repeated one more time for a total of three rounds ofselection.

Plaque Purification of MARMs:

After the third round of selection, the contents of ten independentwells were chosen at random and used for plaque purification of MARMs.The remaining supernatants were mixed 1:1 with 50% sucrose solution andimmediately frozen at −80° C. Supernatants were diluted 1:10, 1:100, and1:1000 in growth medium and incubated with 30 μg/ml of SYNAGIS® for onehour prior to infection. 1 ml of virus inoculum was overlayed onmonolayers of HEp-2 cells in 60 mm round culture dishes (1×10⁶cells/dish) and incubated for 4 hours in growth conditions. Followinginfection the inoculum was carefully aspirated and cells were overlayedwith 3 ml growth medium supplemented with 0.8% low melting temperatureagarose (Gibco BRL), and containing 30 μg/ml of SYNAGIS®. Dishes werereturned to the incubator after complete solidification of agarose andmonitored daily for plaque formation. Uninfected controls and wild typeRSV control plates were set up for comparison. After five to six days,each plate was overlayed with an additional 2 ml of 0.8% agarose ingrowth medium supplemented with 50 μg/ml neutral red. Following anovernight incubation in growth conditions, plaques were scored andpicked for a second round of purification.

Amplification of Clonal MARMs:

Following a second round of plaque purification two clones from eachisolate were expanded for production of high titer viral stocks.Individual plaques were picked with the aid of a pipet tip and incubatedin 0.1 ml of fresh medium at 4° C. overnight to elute the virus. Eachaliquot was used to infect HEp-2 cells in flat bottom 96-well plates(1×10⁴ cells/well) in the presence of 30 μg/ml SYNAGIS®. After five daysthe entire well content was used to infect HEp-2 cells in the presenceof 30 μg/ml of SYNAGIS® in 24-well plates. Each inoculum wassubsequently expanded in the presence of 30 μg/ml of SYNAGIS® to a T-25flask (1×10 ⁶cells/flask) and 5 mls of high titer virus stock wereproduced. MARM stocks were frozen as described above.

F Protein cDNA Synthesis and DNA Sequencing:

In order to determine the nucleotide sequence of an approximately 400nucleotide region of the F protein gene thought to contain the epitopefor SYNAGIS®, First strand cDNA synthesis was performed with totalcellular RNAs isolated from MARM-infected HEp-2 cells at 4 dayspost-infection. Amplification of a fragment of the F protein for DNAsequencing was performed as described in Materials section. AmplifiedMARM F-protein cDNAs were purified by phenol/chloroform extraction andethanol precipitation, and used in a PCR sequencing reaction withgene-specific oligos and Perkin-Elmer Cetus Big-Dye Terminator reactionmix to sequence the relevant region.

Immunofluorescence Assay (IFA):

Cells infected with RSV isolates were tested for anti-RSV binding bySYNAGIS® and Control Pan RSV MAb Pool, as follows. Four to five dayRSV-infected HEp-2 cultures were mixed with PBS and centrifuged at 300×gfor 5 minutes at room temperature. Pellets were resuspended in a smallvolume of PBS for analysis. Five to ten microliters of each cellsuspension were spotted per 5 mm well on acetone washed 12-well HTCsuper cured glass slides and allowed to air dry. Slides were fixed incold (−20° C.) acetone for 10 minutes. Reactions were blocked byspotting 10 μl of 1% BSA in PBS into each well and incubating for 10minutes at room temperature. Slides were washed three times in1×PBS/0.1% Tween-20 and air-dried. Ten microliters of each primaryantibody reagent diluted to 250 ng/ml in blocking buffer were spottedper well and reactions were incubated in a humidified 37° C. environmentfor 30 minutes. Slides were then washed for 1 minute in three changes of1×PBS/0.1% Tween-20 and were air-dried. Ten microliters of appropriatesecondary conjugated antibody reagent diluted to 250 ng/ml in blockingbuffer were added to each respective well and reactions were incubatedin a humidified 37° C. environment for an additional 30 minutes. Slideswere then washed for 1 minute in three changes of 1×PBS/0.1% Tween-20.Five micro liters of 50% glycerol in PBS, 10 mM Tris, pH 8.0, 1 mM EDTAwere spotted in each reaction well, and slides were mounted with coverslips. Each reaction well was subsequently analyzed by fluorescencemicroscopy at 200× power using a B-2A filter (EX 450-490 nm). Positivereactions were scored against an auto-fluorescent background obtainedwith unstained cells or cells stained with secondary reagent alone.

RSV positive reactions were characterized by bright fluorescencepunctuated with small inclusions in the cytoplasm of infected cells.

Microneutralization Assay:

The procedure used here is described in Johnson et al., 1999, J.Infectious Diseases 180:35-40, the disclosure of which is herebyincorporated by reference in its entirety. Briefly, antibody dilutionswere made in triplicate using a 96-well plate. Ten TCID₅₀ of RSV A MARMSwere incubated with serial dilutions of the antibody to be tested for 2hours at 37° C. in the wells of a 96-well plate. The antibodies used inthe assay comprised the heavy chain of SYNAGIS®, the heavy chain ofSYNAGIS® with a point mutation or the heavy chain of A4B4, and the lightchain of SYNAGIS®, the light chain of SYNAGIS® with point mutations, thelight chain of A4B4 with point mutations, the light chain of A4B4 withpoint mutations, the light chain of L1FR (a.k.a. 1X-493L1FR) or thelight chain of L1FR with point mutations. Mab 13/19 was used in theassay as a positive control. RSV susceptible HEp-2 cells (2.5×10⁴) werethen added to each well and cultured for 5 days at 37° C. in 5% CO₂.After 5 days, the medium was aspirated and cells were washed and fixedto the plates with 80% methanol and 20% PBS. RSV replication was thendetermined by F protein expression. Fixed cells were incubated with abiotin-conjugated anti-F protein monoclonal antibody (pan F protein,C-site-specific MAb 133-1H) washed and horseradish peroxidase conjugatedavidin was added to the wells. The wells were washed again and turnoverof substrate TMB (thionitrobenzoic acid) was measured at 450 nm. Theresults from the assay for the monoclonal antibodies are shown in Table19 infra.

Results and Discussion

The binding activity of SYNAGIS® was tested by IFA against a panel of 20RSV A/Long MARMs obtained by three rounds of selection on HEp-2 cells inthe presence of SYNAGIS®. A pool of monoclonal antibodies against thefusion, glycoprotein, and nuclear proteins of RSV (Control Pan RSV MAbPool) was used as a positive control for detection of RSV. Subtyping ofRSV MARMs was performed with two monoclonal antibodies that distinguishtype A and type B glycoproteins. As summarized in Table 17, lack ofbinding activity by SYNAGIS® was demonstrated in all 20 MARMs.Contrasting with lack of binding by SYNAGIS®, binding of the Control PanRSV MAb Pool was demonstrated for all MARMs tested. All 20 MARMs wereclassified as RSV type A. Wild type RSV A/Long infected HEp-2 cellsbound SYNAGIS®, Pan RSV MAb Pool, and RSV Type A MAb, but failed toreact with RSV Type B MAb, as expected.

DNA sequencing analysis of an approximately 400-nucleotide region of theRSV F protein cDNA encompassing the proposed SYNAGIS® epitope revealed asingle mutation at the amino-acid level at position 272. Table 18 showsthe amino acid change at position 272 in twelve isolates sequenced todate. Although the entire nucleotide sequence of RSV MARMs F protein hasnot been determined, these results suggest that amino acid 272 is acritical residue in modulating the binding of SYNAGIS® to its epitope.

The ability of various monoclonal antibodies to neutralize thereplication of RSV A MARMs was determined. As shown in Table 19, theability of the monoclonal antibodies to neutralize the replication ofRSV MARMs varied depending upon the amino acid sequence of the heavychain (HC) and light chain (LC) of the antibody.

TABLE 17 Characterization of anti-RSV Binding Activity by SYNAGIS ®,Control Pan RSV MAb Pool (anti-F, G, N proteins), anti-RSV Type A MAb,and anti-RSV Type B MAb by Immunofluorescence Assay (IFA) on RSV A/LongMARMs. Reactivity w/ Reactivity w/ Reactivity w/ Reactivity w/ RSV MARMSYNAGlS ® anti-RSV MAb Pool anti-RSV type A MAb Anti-RSV type B MAb B1 − + + − B2  − + + − B3  − + + − B4  − + + − B5  − + + − B6  − + + − B7 − + + − B8  − + + − B9  − + + − B10 − + + − B11 − + + − B12 − + + − B13− + + − B14 − + + − B15 − + + − B16 − + + − B17 − + + − B18 − + + − B19− + + − B20 − + + − Wt RSV A/ + + + −

TABLE 18 Amino acid sequence of a region of the wild type RSV A/Long andMARMs F Protein encompassing the proposed SYNAGIS ® epitope. IsolateAmino Acid Sequence (Position number) Wild type 266 267 268 269 270 271272 273 274 275 276 277 278 279 RSV Long I T N D Q K K L M S N N V QMARM I T N D Q K N L M S N N V Q B1 MARM I T N D Q K M L M S N N V Q B2MARM I T N D Q K M L M S N N V Q B3 MARM I T N D Q K M L M S N N V Q B4MARM I T N D Q K M L M S N N V Q B6 MARM I T N D Q K T L M S N N V Q B7MARM I T N D Q K M L M S N N V Q B8 MARM I T N D Q K Q L M S N N V Q B9MARM I T N D Q K T L M S N N V Q B10 MARM I T N D Q K M L M S N N V QB13 MARM I T N D Q K Q L M S N N V Q B14 MARM I T N D Q K M L M S N N VQ B15

TABLE 19 MARM analysis by Microneutralization Assay RSVMicroneutralization Assay On RSV A MARMs to Synagis with RSV MonoclonalAntibody Amino Acid Change K272Q K272N K272M K272T Antibody MARMs toSYNAGIS ® HC/LC MARM B9 MARM B1 MARM B2 MARM B7 Note SYNAGIS ®/SYNAGIS ®− − − − Purified Ab A4B4/A4B4 + + + + Purified Ab A4B4/SYNAGIS ® + + + −Purified Ab SYNAGIS ®/A4B4 − − − − Purified Ab A4B4/L1FR + + + −Purified Ab A4B4/L1FR S28R + + + + Purified Ab A4B4/L1FR S28R,S52F + + + + Purified Ab A4B4/L1FR-28R, 52F, F93 − − − − Purified AbA4B4/A4b428S + + + + Purified Ab A4B4/A4b452S + + + + Purified Ab Mab13/19 + + + + Purified Ab SYNAGIS ®/K53F − − − − 293H sup SYNAGIS ®/S28R− − − − 293H sup SYNAGIS ®/Q26S − − − − 293H sup SYNAGIS ®/A55D − − − −293H sup SYNAGIS ®/K24S − − − − 293H sup SYNAGIS ®/C25A − − − − 293H supSYNAGIS ®/L27S − − − − 293H sup SYNAGIS ®/S52F − − − − 293H supSYNAGIS ®/L105V − − − − 293H sup T98F/SYNAGIS ® − − − − Purified abS32A/SYNAGIS ® − − − − 293H sup S95D/SYNAGIS ® − − − − 293H supD58H/SYNAGIS ® − − − − 293H sup A105Q/SYNAGIS ® − − − − 293H supS65D/SYNAGIS ® − − − − 293H sup W100F/SYNAGIS ® − − − − 293H sup + =neutralization detected; − = no neutralization detected

13. EXAMPLE In Vitro Isolation of A4B4 Specific Monoclonal AntibodyResistant Mutants (MARM) of RSV Strain A/Long

This example demonstrates that MARMs can be isolated from RSV laboratorystrain A/Long upon multiple rounds of selection in the presence of A4B4

Materials

A4B4 (Lot # 524-9, 3.57 mg/ml), Control Pan RSV MAb Pool (ChemiconMAB858-4, a blend of three MAbs anti-F, G, and N proteins), anti-RSVType A MAb (Chemicon MAB858-1), and anti-RSV Type B MAb (ChemiconMAB858-2) were used in this study. Secondary detecting reagents wereeither Alexa™488 conjugated Qoat F (ab′)₂ anti-Mouse or Human IgG (H+L).Virus bank of RSV A/Long strain NWVB020500 (2.38×10⁷ TCID₅₀/ml)propagated from Master Virus Bank 031797. HEp-2 cells were propagated inEMEM supplemented with 10% FBS and 2 mM L-Gln in a 37° C., 5% CO₂environment. Messanger RNA was purified from the infected cells usingthe mRNA Capture Kit (Roche). The mRNA samples were used to make cDNAusing the reagents from the cDNA First Strand Reacition Kit (Roche),followed by amplification of the RSV F protein gene by the PolymeraseChain Reaction (PCR) using gene specific primers.

Methods

Selection of MARMs:

4×10⁵ HEp-2 cells were seeded per well of a 24-well plate in growthmedium (EMEM, 10% FBS, 2 mM L-Gln) and incubated overnight in growthconditions (37° C., 5% CO₂). 44 wells were seeded for individual MARMselection. Prior to infection, a fresh vial of virus bank RSV A/Long wasthawed rapidly at 37° C. and the virus titer adjusted to 4×10⁶ pfu/ml inHEp-2 growth medium. A4B4 was added to the virus inoculum at a finalconcentration of 2 μg/ml, and the mixture was incubated at 37° C. forone hour. An aliquot of RSV was incubated with an irrelevant Human IgG1Mab (MEDI-507) and was used as a negative control. An uninfected controlwell was also set up for each plate. Cells were washed once with freshmedium and were overlayed with 100 μl of RSV A/Long virus 30 stock/MAbmixture. Cells were incubated for four hours in growth conditionsfollowed by addition of 1 ml of growth medium to each well. Cytopathiceffect (CPE) was monitored on a daily basis by light microscopy.Following seven days of selection the contents of each well weresupplemented with a further 4 μg/ml of A4B4 or irrelevant Human IgG 1Mab, and were used to infect freshly seeded HEp-2 cells (4×10⁵cells/well of 24-well plate). After a further seven days of selectionthe process was repeated one more time for a total of three rounds ofselection. The contents of wells showing clear CPE were mixed 1:1 with50% sucrose solution and immediately frozen at −80° C.

Plaque Purification of MARMs:

After the third round of selection, the contents of two independentwells were chosen at random and used for plaque purification of MARMs. Afresh vial of MARM stock (was frozen after third round of selection) wasthawed at room temperature and was diluted 1:10, 1:100, and 1:1000 ingrowth medium and incubated with 4 μg/ml of A4B4 for one hour prior toinfection. 0.5 ml of virus inoculum was overlayed on monolayers of HEp-2cells in 6 well plates (5×10⁵ cells/well) and incubated for 4 hours ingrowth conditions. Following infection the inoculum was carefullyaspirated and cells were overlayed with 2 ml growth medium supplementedwith 0.8% low melting temperature agarose (Gibco BRL), and containing 4μg/ml of A4B4. Dishes were returned to the incubator after completesolidification of agarose and monitored daily for plaque formation.Uninfected controls and wild type RSV control plates were set up forcomparison. After five to six days, each plate was overlayed with anadditional 2 ml of 0.8% agarose in growth medium supplemented with 50μg/ml neutral red. Following an overnight incubation in growthconditions, plaques were scored and picked for a second round ofpurification.

Amplification of Clonal MARMs:

Following a second round of plaque purification three clones from eachisolate were expanded for production of high titer viral stocks.Individual plaques were picked with the aid of a pipet tip and incubatedin 0.2 ml of fresh medium at 4° C. overnight to elute the virus. Eachaliquot was used to infect HEp-2 cells in flat bottom 24-well plates(2.5×10⁵ cells/well-seeded day before) in the presence of 4 μg/ml A4B4.After five days the entire well content was used to infect HEp-2 cellsin the presence of 4 μg/ml of A4b4 in 24-well plates. Each inoculum wassubsequently expanded in the presence of 4 μg/ml of A4b4 to a T-25 flask(6.5×10⁵ cells/flask—seeded day before) and 5 mls of high titer virusstock were produced. MARM stocks were frozen as described above.

F Protein cDNA Synthesis and DNA Sequencing:

In order to determine the nucleotide sequence of an approximately 800nucleotide region of the F protein gene thought to contain the epitopefor SYNAGIS®, First strand cDNA synthesis was performed with mRNAsisolated from MARM-infected HEp-2 cells at 4 days post-infection. RSVinfected Hep2 cells were lysed in 150 μl of lysis buffer provided withthe mRNA capture kit. Biotinylated oligo dT was diluted 1:10 withnuclease free H₂O and 4 μl was added to each lysate. Samples wereincubated 10 minutes at 42° C. to allow the oligo dT to anneal to themRNA. A 50 μl aliquot of the lysate was transferred to a streptavidincoated PCR tube and incubated for three minutes at 37° C. The lysateswere removed from the PCR tubes and discarded. The RNA captured in thetubes was washed three times with 200 μl of wash buffer.

RT reactions were performed using reagents from the First Strand cDNAkit (Roche Molecular Biochemicals). A master mix was prepared so thateach reaction contained 5 μl 10× buffer, 5 μl dNTPs, 10 μl MgCl₂, 1 μlgelatin, 2 μl RNase Inhibitor, 2 μl AMV-RT, in a final volume of 50 μl.Fifty microliter aliquots of the master mix were transferred to the PCRtubes containing the captured mRNA. Samples were placed in athermalcycler and incubated for two hours at 42° C. The cDNA reactionmix was then removed from the PCR tubes and discarded. The cDNA capturedin the PCR tubes was washed with 200 μl of wash buffer To obtain enoughof the RSV F protein gene for sequence analysis, the cDNA was subjectedto PCR using gene specific primers. Each reactions contained 10 mMTris-HCl, pH 8.3, 50 mM KCl, 2.5 mM MgCl₂, 200 μM dNTPs, 125 ng of eachforward (5′AGTGTCTTAACCAGCAAAGTGTTAGA 3′; SEQ ID NO:258) and reverse (5′TCATTGACTTGAGATATTGATGCATC 3′; SEQ ID NO:259) primer, and 2.5 units ofTaq polymerase (PE Biosystems) in a final volume of 50 μl. Thetemperature profile for all reactions was 95° C. for 2 min, followed by40 cycles of 95° C. for 30 sec., 55° C. for 45 sec, 72° C. for 45 sec,with a final extension at 72° C. for 10 minutes.

All PCR products were separated by electrophoresis on a 2% agarose gelin 1× TBE and visualized by ethidium bromide fluorescence.

PCR products were purified using Qiaquick spin columns (Qiagen andsequenced using the Big Dye-terminator PRISM kit (Applied Biosystems(ABI)). The reactions contained 70 ng of PCR product as template, 3pmols of primer, and 8.0 μl of the PRISM dye-terminator reaction mix ina final volume of 20 μl. The reactions were subjected to thermal cyclingaccording to ABI's dye-terminator sequencing instructions.Unincorporated dyes were removed from the extension products usingCentri-Sep spin columns (Princeton Separations). Extension products weredried in a Savant Speed Vac and then dissolved in 10 μl HiDi Formamide(ABI) loading buffer. Samples were applied by electrophoresis in an ABI3100 automated sequencer. Sequence data collected by the sequencer wasanalyzed using Lasargene (DNA Star).

Immunofluorescence Assay (IFA):

Cells infected with RSV isolates were tested for anti-RSV binding byA4B4, SYNAGIS® and Control Pan RSV MAb Pool, as follows. Four to fiveday RSV-infected HEp-2 cultures were mixed with PBS and centrifuged at300×g for 5 minutes at room temperature. Pellets were resuspended in asmall volume of PBS for analysis. Five to ten micro liters of each cellsuspension were spotted per 5 mm well on acetone washed 12-well HTCsupercured glass slides and allowed to air dry. Slides were fixed incold (−20° C.) acetone for 10 minutes. Reactions were blocked byspotting 10 μl of 1% BSA in PBS into each well and incubating for 10minutes at room temperature. Slides were washed three times in 1×PBS/0.1% Tween-20 and air-dried. Ten micro liters of each primaryantibody reagent diluted to 250 ng/ml in blocking buffer were spottedper well and reactions were incubated in a humidified 37° C. environmentfor 30 minutes. Slides were then washed for 1 minute in three changes of1× PBS/0.1% Tween-20 and were air-dried. Ten micro liters of appropriatesecondary conjugated antibody reagent diluted to 250 ng/ml in blockingbuffer were added to each respective well and reactions were incubatedin a humidified 37° C. environment for an additional 30 minutes. Slideswere then washed for 1 minute in three changes of 1× PBS/0.1% Tween-20.Five micro liters of 50% glycerol in PBS, 10 mM Tris, pH 8.0, 1 mM EDTAwere spotted in each reaction well, and slides were mounted with coverslips. Each reaction well was subsequently analyzed by fluorescencemicroscopy at 200× power using a B-2A filter (EX 450-490 nm). Positivereactions were scored against an auto fluorescent background obtainedwith unstained cells or cells stained with secondary reagent alone.

RSV positive reactions were characterized by bright fluorescencepunctuated with small inclusions in the cytoplasm of infected cells.

Microneutralization Assay:

The procedure used here is described in Johnson et al., 1999, J.Infectious Diseases 180:35-40, the disclosure of which is herebyincorporated by reference in its entirety. Briefly, antibody dilutionswere made in triplicate using a 96-well plate. Ten TCID₅₀ of RSV A MARMSwere incubated with serial dilutions of the antibody to be tested for 2hours at 37° C. in the wells of a 96-well plate. The antibodies used inthe assay comprised the heavy and light chain of SYNAGIS®, the heavy andlight chain of A4b4, the combination of the heavy and light chain ofSYNAGIS® and A4b4, the SYNAGIS® heavy chain or light chain with a pointmutation in light chain or heavy chain, or A4b4 heavy chain with pointmutations in light chain. Mab 13/19 was used as a positive control inthe assay. RSV susceptible HEp-2 cells (2.5×10⁴) were then added to eachwell and cultured for 5 days at 37° C. in 5% CO₂. After 5 days, themedium was aspirated and cells were washed and fixed to the plates with80% methanol and 20% PBS. RSV replication was then determined by Fprotein expression. Fixed cells were incubated with a biotin-conjugatedanti-F protein monoclonal antibody (pan F protein, C-site-specific MAb133-1H) washed and horseradish peroxidase conjugated avidin was added tothe wells. The wells were washed again and turnover of substrate TMB(thionitrobenzoic acid) was measured at 450 nm. The results from theassay for the monoclonal antibodies are shown in Table 22 infra.

Results and Discussion

The binding activity of A4B4 was tested by IFA against a panel of RSVA/Long MARMs obtained by three rounds of selection on HEp-2 cells in thepresence of SYNAGIS®. A pool of monoclonal antibodies against thefusion, glycoprotein, and nuclear proteins of RSV (Control Pan RSV MAbPool) was used as a positive control for detection of RSV. Subtyping ofRSV MARMs was performed with two monoclonal antibodies that distinguishtype A and type B glycoproteins. As summarized in Table 20, lack ofbinding activity by A4B4 and SYNAGIS® was demonstrated in MARMs.Contrasting with lack of binding by A4B4 and SYNAGIS®, binding of theControl Pan RSV MAb Pool was demonstrated for all MARMs tested. BothMARMs were classified as RSV type A. Wild type RSV A/Long infected HEp-2cells bound to A4B4 and SYNAGIS®, Pan RSV MAb Pool, and RSV Type A MAb,but failed to react with RSV Type B MAb, as expected.

DNA sequencing analysis of an approximately 800-nucleotide region of theRSV F protein cDNA encompassing the proposed A4B4 epitope revealedmutation at the amino-acid level at position 272 and 276. Table 21 showsthe amino acid change in isolates sequenced to date. Although the entirenucleotide sequence of RSV MARMs F protein has not been determined,these results suggest that amino acid 272 and 276 is a critical residuein modulating the binding of A4B4 to its epitope.

The ability of various monoclonal antibodies to neutralize thereplication of a RSV A MARM was determined. As shown in Table 22, theability of the monoclonal antibodies to neutralize the replication of aRSV MARM varied depending upon the amino acid sequence of the heavychain (HC) and light chain (LC) of the antibody.

TABLE 20 Characterization of anti-RSV Binding Activity by A4B4,Synagis ®, Control Pan RSV MAb Pool (anti-F, G, N proteins), anti-RSVType A MAb, and anti-RSV Type B MAb by Immunofluorescence Assay (IFA) onRSV A/Long MARMs. Reactivity w/ Reactivity w/ Reactivity w/ Reactivityw/ Reactivity RSV MARM sample Synagis ® Anti-RSV MAb Pool Anti-RSV typeA MAb Anti-RSV type B MAb A4B4 MARM #6  − + + − − MARM #9  − + + − −MARM #10 − + + − − MARM #11 − + + − − Wt + + + − +

TABLE 21 Amino acid sequence of a region of the wild type RSV A/Long andMARMs F Protein. Isolate Amino Acid Sequence (Position number) Wild type266 267 268 269 270 271 272 273 274 275 276 277 278 279 RSV I T N D Q KK L M S N N V Q MARM I T N D Q K E L M S Y N V Q #10 MARM I T N D Q K EL M S N N V Q #6 MARM I T N D Q K E L M S N N V Q #9 MARM I T N D Q K EL M S N N V Q #11 MARM I T N D Q K E L M S N N V Q #14

TABLE 22 MARM analysis by Microneutralization Assay RSVMicroneutralization Assay On RSV A MARMs to A4B4 with RSV MonoclonalAntibody K272E, N276Y Antibody MARM to HC/LC MARM 10 NoteSYNAGIS ®/SYNAGIS ® − Purified Ab A4B4/A4B4 − Purified Ab A4b4/SYNAGIS ®− Purified Ab SYNAGIS ®/A4B4 − Purified Ab A4B4/L1FR − Purified AbA4B4/L1FR S28R − Purified Ab A4B4/L1FR S28R, S52F − Purified AbA4B4/L1FR-28R, 52F, 93F − Purified Ab A4B4/A4B428S − Purified AbA4B4/A4B452S − Purified Ab Mab 13/19 + Purified Ab + = neutralizationdetected; − = no neutralization detected

14. EXAMPLE In Vitro Isolation of A4B4 Specific Monoclonal AntibodyResistant Mutants (MARM) of MARM B9(MARM of RSV Strain A/Long toSynagis)

This example demonstrates that MARMs can be isolated from MARM of RSV Along to Synagis (MARM B9) upon multiple rounds of selection in thepresence of A4B4

Materials

A4B4 (Lot # 524-9, 3.57 mg/ml), Control Pan RSV MAb Pool (ChemiconMAB858-4, a blend of three MAbs anti-F, G, and N proteins), anti-RSVType A MAb (Chemicon MAB858-1), and anti-RSV Type B MAb (ChemiconMAB858-2) were used in this study. Secondary detecting reagents wereeither Alexa™488 conjugated Goat F (ab′)₂ anti-Mouse or Human IgG (H+L).MARM B9 (1.78×10⁶ TCID₅ ml) was used here. HEp-2 cells were propagatedin EMEM supplemented with 10% FBS and 2 mM L-Gln in a 3.7° C., 5% CO₂environment. Messanger RNA was purified from the infected cells usingthe mRNA Capture Kit (Roche). The mRNA samples were used to make cDNAusing the reagents from the cDNA First Strand Reacition Kit (Roche),followed by amplification of the RSV F protein gene by the PolymeraseChain Reaction (PCR) using gene specific primers.

Methods

Selection of MARMs:

4×10⁵ HEp-2 cells were seeded per well of a 24-well plate in growthmedium (EMEM, 10% FBS, 2 mM L-Gln) and incubated overnight in growthconditions (37° C., 5% CO₂). 44 wells were seeded for individual MARMselection. Prior to infection, a fresh vial of virus bank MARM B9 wasthawed rapidly at 37° C. and the virus titer adjusted to 6×10⁵ pfu/ml inHEp-2 growth medium. A4B4 was added to the virus inoculum at a finalconcentration of 2 μg/ml, and the mixture was incubated at 37° C. forone hour. An aliquot of RSV was incubated with an irrelevant Human IgG1Mab (MEDI-507) and was used as a negative control. An uninfected controlwell was also set up for each plate. Cells were washed once with freshmedium and were overlayed with 100 μl of RSV A/Long virus stock/MAbmixture. Cells were incubated for four hours in growth conditionsfollowed by addition of 1 ml of growth medium to each well. Cytopathiceffect (CPE) was monitored on a daily basis by light microscopy.Following seven days of selection the contents of each well weresupplemented with a further 4 μg/ml of A4B4 or irrelevant Human IgG1Mab, and were used to infect freshly seeded HEp-2 cells (4×10⁵cells/well of 24-well plate). After a further seven days of selectionthe process was repeated one more time for a total of three rounds ofselection. The contents of wells showing clear CPE were mixed 1:1 with50% sucrose solution and immediately frozen at −80° C.

Plaque Purification of MARMs:

After the third round of selection, the contents of independent wellswere used for plaque purification of MARMs. A fresh vial of MARM stock(was frozen after third round of selection) was thawed at roomtemperature and was diluted 1:10, 1:100, and 1:1000 in growth medium andincubated with 4 μg/ml of A4B4 for one hour prior to infection. 0.5 mlof virus inoculum was overlayed on monolayers of HEp-2 cells in 6 wellplates (5×10⁵ cells/well) and incubated for 4 hours in growthconditions. Following infection the inoculum was carefully aspirated andcells were overlayed with 2 ml growth medium supplemented with 0.8% lowmelting temperature agarose (Gibco BRL), and containing 4 μg/ml of A4B4.Dishes were returned to the incubator after complete solidification ofagarose and monitored daily for plaque formation. Uninfected controlsand MARM B9 RSV control plates were set up for comparison. After five tosix days, each plate was overlayed with an additional 2 ml of 0.8%agarose in growth medium supplemented with 50 μg/ml neutral red.Following an overnight incubation in growth conditions, plaques werescored and picked for a second round of purification.

Amplification of clonal MARMs:

Following a second round of plaque purification three clones fromisolate were expanded for production of high titer viral stocks.Individual plaques were picked with the aid of a pipet tip and incubatedin 0.2 ml of fresh medium at 4° C. overnight to elute the virus. Eachaliquot was used to infect HEp-2 cells in flat bottom 24-well plates(2.5×10⁵ cells/well-seeded day before) in the presence of 4 μg/ml A4B4.After five days the entire well content was used to infect HEp-2 cellsin the presence of 4 μg/ml of A4B4 in 24-well plates. Each inoculum wassubsequently expanded in the presence of 4 μg/ml of A4B4 to a T-25 flask(6.5×10⁵ cells/flask—seeded day before) and 5 mls of high titer virusstock were produced. MARM stocks were frozen as described above.

F Protein cDNA Synthesis and DNA Sequencing:

In order to determine the nucleotide sequence of an approximately 800nucleotide region of the F protein gene thought to contain the epitopefor SYNAGIS®, First strand cDNA synthesis was performed with mRNAsisolated from MARM-infected HEp-2 cells at 4 days post-infection. RSVinfected Hep2 cells were lysed in 150 μl of lysis buffer provided withthe mRNA capture kit. Biotinylated oligo dT was diluted 1:10 withnuclease free H₂O and 4 μl was added to each lysate. Samples wereincubated 10 minutes at 42° C. to allow the oligo dT to anneal to themRNA. A 50 μl aliquot of the lysate was transferred to a streptavidincoated PCR tube and incubated for three minutes at 37° C. The lysateswere removed from the PCR tubes and discarded. The RNA captured in thetubes was washed three times with 200 μl of wash buffer.

RT reactions were performed using reagents from the First Strand cDNAkit (Roche Molecular Biochemicals). A master mix was prepared so thateach reaction contained 5 μl 10× buffer, 5 μl dNTPs, 10 μl MgCl₂, 1 μlgelatin, 2 μl RNase Inhibitor, 2 μl AMV-RT, in a final volume of 50 μl.Fifty microliter aliquots of the master mix were transferred to the PCRtubes containing the captured mRNA. Samples were placed in athermalcycler and incubated for two hours at 42° C. The cDNA reactionmix was then removed from the PCR tubes and discarded. The cDNA capturedin the PCR tubes was washed with 200 μl of wash buffer To obtain enoughof the RSV F protein gene for sequence analysis, the cDNA was subjectedto PCR using gene specific primers. Each reactions contained 10 mMTris-HCl, pH 8.3, 50 mM KCl, 2.5 mM MgCl₂, 200 μM dNTPs, 125 ng of eachforward (5′AGTGTCTTAACCAGCAAAGTGTTAGA 3′; SEQ ID NO:258) and reverse (5′TCATTGACTTGAGATATTGATGCATC 3′; SEQ ID NO:259) primer, and 2.5 units ofTaq polymerase (PE Biosystems) in a final volume of 50 μl. Thetemperature profile for all reactions was 95° C. for 2 min, followed by40 cycles of 95° C. for 30 sec., 55° C. for 45 sec, 72° C. for 45 sec,with a final extension at 72° C. for 10 minutes.

All PCR products were separated by electrophoresis on a 2% agarose gelin 1× TBE and visualized by ethidium bromide fluorescence.

PCR products were purified using Qiaquick spin columns (Qiagen andsequenced using the Big Dye-terminator PRISM kit (Applied Biosystems(ABI)). The reactions contained 70 ng of PCR product as template, 3pmols of primer, and 8.0 μl of the PRISM dye-terminator reaction mix ina final volume of 20 μl. The reactions were subjected to thermal cyclingaccording to ABI's dye-terminator sequencing instructions.Unincorporated dyes were removed from the extension products usingCentri-Sep spin columns (Princeton Separations). Extension products weredried in a Savant Speed Vac and then dissolved in 10 μl HiDi Formamide(ABI) loading buffer. Samples were applied by electrophoresis in an ABI3100 automated sequencer. Sequence data collected by the sequencer wasanalyzed using Lasargene (DNA Star).

Immunofluorescence Assay (IFA):

Cells infected with RSV isolates were tested for anti-RSV binding byA4B4, SYNAGIS®, and Control Pan RSV MAb Pool, as follows. Four to fiveday RSV-infected HEp-2 cultures were mixed with PBS and centrifuged at300×g for 5 minutes at room temperature. Pellets were resuspended in asmall volume of PBS for analysis. Five to ten micro liters of each cellsuspension were spotted per 5 mm well on acetone washed 12-well HTCsuper cured glass slides and allowed to air dry. Slides were fixed incold (−20° C.) acetone for 10 minutes. Reactions were blocked byspotting 10 μl of 1% BSA in PBS into each well and incubating for 10minutes at room temperature. Slides were washed three times in 1×PBS/0.1% Tween-20 and air-dried. Ten micro liters of each primaryantibody reagent diluted to 250 ng/ml in blocking buffer were spottedper well and reactions were incubated in a humidified 37° C. environmentfor 30 minutes. Slides were then washed for 1 minute in three changes of1× PBS/0.1% Tween-20 and were air-dried. Ten micro liters of appropriatesecondary conjugated antibody reagent diluted to 250 ng/ml in blockingbuffer were added to each respective well and reactions were incubatedin a humidified 37° C. environment for an additional 30 minutes. Slideswere then washed for 1 minute in three changes of 1× PBS/0.1% Tween-20.Five micro liters of 50% glycerol in PBS, 10 mM Tris, pH 8.0, 1 mM EDTAwere spotted in each reaction well, and slides were mounted with coverslips. Each reaction well was subsequently analyzed by fluorescencemicroscopy at 200× power using a B-2A filter (EX 450-490 nm). Positivereactions were scored against an auto fluorescent background obtainedwith unstained cells or cells stained with secondary reagent alone.

RSV positive reactions were characterized by bright fluorescencepunctuated with small inclusions in the cytoplasm of infected cells.

Microneutralization Assay:

The procedure used here is described in Johnson et al., 1999, J.Infectious Diseases 180:35-40, the disclosure of which is herebyincorporated by reference in its entirety. Briefly, antibody dilutionswere made in triplicate using a 96-well plate. Ten TCID₅₀ of RSV A MARMSwere incubated with serial dilutions of the antibody to be tested for 2hours at 37° C. in the wells of a 96-well plate. The antibodies used inthe assay comprised the heavy chain of SYNAGIS® or the heavy chain ofA4B4, and the light chain of SYNAGIS®, the light chain of A4B4, thelight chain of A4B4 with a point mutation, the light chain of L1FR orthe light chain of L1FR with point mutations. Mab 13/19 was used as apositive control in the assays. RSV susceptible HEp-2 cells (2.5×10⁴)were then added to each well and cultured for 5 days at 37° C. in 5%CO₂. After 5 days, the medium was aspirated and cells were washed andfixed to the plates with 80% methanol and 20% PBS. RSV replication wasthen determined by F protein expression. Fixed cells were incubated witha biotin-conjugated anti-F protein monoclonal antibody (pan F protein,C-site-specific MAb 133-1H) washed and horseradish peroxidase conjugatedavidin was added to the wells. The wells were washed again and turnoverof substrate TMB (thionitrobenzoic acid) was measured at 450 nm. Theresults from the assay for the monoclonal antibodies are shown in Table25 infra.

Results and Discussion

The binding activity of A4B4 was tested by IFA against a MARM obtainedby three rounds of selection on HEp-2 cells in the presence of A4B4. Apool of monoclonal antibodies against the fusion, glycoprotein, andnuclear proteins of RSV (Control Pan RSV MAb Pool) was used as apositive control for detection of RSV. Subtyping of RSV MARMs wasperformed with two monoclonal antibodies that distinguish type A andtype B glycoproteins. As summarized in Table 23, lack of bindingactivity by A4B4 and SYNAGIS® was demonstrated in both MARMs.Contrasting with lack of binding by A4B4 and SYNAGIS®, binding of theControl Pan RSV MAb Pool was demonstrated for all MARMs tested. BothMARMs were classified as RSV type A. Wild type RSV A/Long infected HEp-2cells bound to A4B4 and SYNAGIS®, Pan RSV MAb Pool, and RSV Type A MAb,but failed to react with RSV Type B MAb, as expected.

DNA sequencing analysis of an approximately 800 nucleotide region of theRSV F protein cDNA encompassing the proposed A4B4 epitope revealedmutation at the amino-acid level at position 272 and 262. Table 24 showsthe amino acid change in isolates sequenced to date. Although the entirenucleotide sequence of RSV MARMs F protein has not been determined,these results suggest that amino acid 272 and 262 is a critical residuein modulating the binding of A4B4 to its epitope.

The ability of various monoclonal antibodies to neutralize thereplication of RSV A MARMs was determined. As shown in Table 25, theability of the monoclonal antibodies to neutralize the replication ofRSV MARMs varied depending upon the amino acid sequence of the heavychain (HC) and light chain (LC) of the antibody.

TABLE 23 Characterization of anti-RSV Binding Activity by A4B4,SYNAGIS ®, Control Pan RSV MAb Pool (anti-F, G, N proteins), anti-RSVType A MAb, and anti-RSV Type B MAb by Immunofluorescence Assay (IFA) onRSV A/Long MARMs. Reactivity w/ Reactivity w/ Reactivity w/ Reactivityw/ Reactivity RSV MARM sample Synagis ® Anti-RSV MAb Pool Anti-RSV typeA MAb Anti-RSV type B MAb A4B4 MARM #13 − + + − − B9 − + + − + Wt + + +− −

TABLE 24 Amino acid sequence of a region of the wild type RSV A/Long andMARMs F Protein. Isolate Amino Acid Sequence (Position number) Wild typeRSV 262 266 267 268 269 270 271 272 273 274 275 276 277 278 279 Long A NI T N D Q K K L M S N N V Q MARM #13 262 266 267 268 269 270 271 272 273274 275 276 277 278 279 K I T N D Q K Q L M S N N V Q

TABLE 25 MARM analysis by Microneutralization Assay RSVMicroneutralization Assay On RSV A MARMs to A4B4 with RSV MonoclonalAntibody. K272Q, N262K Antibody MARM to SYNAGIS ® & HC/LC A4B4 MARM 13Note SYNAGIS ®/SYNAGIS ® − Purified Ab A4B4/A4B4 − Purified AbA4B4/SYNAGIS ® − Purified Ab SYNAGIS ®/A4B4 − Purified Ab A4B4/L1FR −Purified Ab A4B4/L1FR S28R − Purified Ab A4B4/L1FR S28R, S52F − PurifiedAb A4B4/L1FR-28R, 52F, 93F − Purified Ab A4B4/A4B428S − Purified AbA4B4/A4B452S − Purified Ab Mab 13/19 + Purified Ab + = neutralizationdetected; − = no neutralization detected

15. EXAMPLE Clinical Trials

Antibodies of the invention or fragments thereof tested in in vitroassays and animal models may be further evaluated for safety, toleranceand pharmacokinetics in groups of normal healthy adult volunteers. Thevolunteers are administered intramuscularly, intravenously or by apulmonary delivery system a single dose of 0.5 mg/kg, 3 mg/kg, 5 mg/kg,10 mg/kg or 15 mg/kg of an antibody or fragment thereof whichimmunospecifically binds to a RSV antigen. Each volunteer is monitoredat least 24 hours prior to receiving the single dose of the antibody orfragment thereof and each volunteer will be monitored for at least 48hours after receiving the dose at a clinical site. Then volunteers aremonitored as outpatients on days 3, 7, 14, 21, 28, 35, 42, 49, and 56postdose.

Blood samples are collected via an indwelling catheter or directvenipuncture using 10 ml red-top Vacutainer tubes at the followingintervals: (1) prior to administering the dose of the antibody orantibody fragment; (2) during the administration of the dose of theantibody or antibody fragment; (3) 5 minutes, 10 minutes, 15 minutes, 20minutes, 30 minutes, 1 hour, 2 hours, 4 hours, 8 hours, 12 hours, 24hours, and 48 hours after administering the dose of the antibody orantibody fragment; and (4) 3 days, 7 days 14 days, 21 days, 28 days, 35days, 42 days, 49 days, and 56 days after administering the dose of theantibody or antibody fragment. Samples are allowed to clot at roomtemperature and serum will be collected after centrifugation.

The antibody or antibody fragment is partially purified from the serumsamples and the amount of antibody or antibody fragment in the sampleswill be quantitated by ELISA. Briefly, the ELISA consists of coatingmicrotiter plates overnight at 4° C. with an antibody that recognizesthe antibody or antibody fragment administered to the volunteer. Theplates are then blocked for approximately 30 minutes at room temperatewith PBS-Tween-0.5% BSA. Standard curves are constructed using purifiedantibody or antibody fragment, not administered to a volunteer. Samplesare diluted in PBS-Tween-BSA. The samples and standards are incubatedfor approximately 1 hour at room temperature. Next, the bound antibodyis treated with a labeled antibody (e.g., horseradish peroxidaseconjugated goat-anti-human IgG) for approximately 1 hour at roomtemperature. Binding of the labeled antibody is detected, e.g., by aspectrophotometer.

The concentration of antibody or antibody fragment levels in the serumof volunteers are corrected by subtracting the predose serum level(background level) from the serum levels at each collection intervalafter administration of the dose. For each volunteer the pharmacokineticparameters are computed according to the model-independent approach(Gibaldi et al., eds., 1982, Pharmacokinetics, 2^(nd) edition, MarcelDekker, New York) from the corrected serum antibody or antibody fragmentconcentrations.

Equivalents

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

All publications, patents and patent applications mentioned in thisspecification are herein incorporated by reference into thespecification to the same extent as if each individual publication,patent or patent application was specifically and individually indicatedto be incorporated herein by reference.

1. A method of treating or ameliorating a respiratory syncytial virus(RSV) infection or a symptom thereof, said method comprisingadministering to a human having the RSV infection an effective amount ofan antibody comprising a variable light (VL) domain having the aminoacid sequence of SEQ ID NO: 11, wherein the antibody immunospecificallybinds to a RSV F antigen and the effective amount of the antibodyresults in an effective neutralizing titer of the antibody.
 2. A methodof treating or ameliorating a RSV infection or a symptom thereof, saidmethod comprising administering to a human having the RSV infection aneffective amount of an antibody comprising a variable heavy (VH) domainhaving the amino acid sequence of SEQ ID NO: 48, wherein the antibodyimmunospecifically binds to a RSV F antigen and the effective amount ofthe antibody results in an effective neutralizing titer of the antibody.3. The method of claim 1, wherein the antibody further comprises a VHdomain having the amino acid sequence of SEQ ID NO:
 48. 4. A method oftreating or ameliorating a RSV infection or a symptom thereof, saidmethod comprising administering to a human having the RSV infection aneffective amount of an antibody comprising a VH complementaritydetermining region (CDR)1 having an amino acid sequence of SEQ ID NO:10,a VH CDR2 having the amino acid sequence of SEQ ID NO:19, a VH CDR3having the amino acid sequence of SEQ ID NO:20, a VL CDR1 having theamino acid sequence of SEQ ID NO:39, a VL CDR2 having the amino acidsequence of SEQ ID NO:5, and a VL CDR3 having the amino acid sequence ofSEQ ID NO:6, wherein the antibody immunospecifically binds to a RSV Fantigen and the effective amount of the antibody results in an effectiveneutralizing titer of the antibody.
 5. A method of treating orameliorating a RSV infection or a symptom thereof, said methodcomprising administering to a human having the RSV infection aneffective amount of an antibody comprising a VL chain having the aminoacid sequence of SEQ ID NO: 255, wherein the antibody immunospecificallybinds to a RSV F antigen and the effective amount of the antibodyresults in an effective neutralizing titer of the antibody.
 6. A methodof treating or ameliorating a RSV infection or a symptom thereof, saidmethod comprising administering to having the RSV infection an effectiveamount of an antibody comprising a VH chain having the amino acidsequence of SEQ ID NO: 254, wherein the antibody immunospecificallybinds to a RSV F antigen and the effective amount of the antibodyresults in an effective neutralizing titer of the antibody.
 7. Themethod of claim 6, wherein the antibody further comprises a VL chainhaving the amino acid sequence of SEQ ID NO:
 255. 8. The method of anyone of claims 1, 2, 3, 4, 5, 6 or 7, wherein the effective amount is 15mg/kg or less, 10 mg/kg or less, 5 mg/kg or less or 3 mg/kg or less or1.5 mg/kg or less.
 9. The method of any one of claims 1, 2, 3, 4, 5, 6or 7, wherein the effective neutralizing titer is at least 1 μg/ml, atleast 2 μg/ml, at least 4 μg/ml, at least 6 μg/ml, at least 30 μg/ml, 35μg/ml, at least 40 μg/ml, at least 50 μg/ml, at least 75 μg/ml, at least100 μg/ml, at least 150 μg/ml or at least 200 μg/ml.
 10. The method ofany one of claims 1, 2, 3, 4, 5, 6 or 7, wherein the effectiveneutralizing titer is maintained for at least 20 days, at least 25 daysor at least 30 days after administration of the dose.
 11. The method ofany one of claims 1, 2, 3, 4, 5, 6 or 7, wherein the antibody isadministered by a nebulizer or inhaler.
 12. The method of any one ofclaims 1, 2, 3, 4, 5, 6 or 7, wherein the antibody is administeredintranasally, intramuscularly, intravenously or subcutaneously.
 13. Themethod of any one of claims 1, 2 or 3, wherein the antibody is amonoclonal antibody, chimeric antibody, Fab fragment, F(ab)₂ fragment,single-chain Fv or a single chain antibody.
 14. The method of any one ofclaims 1, 2, 3, 4, 5, 6 or 7, wherein the antibody is administered 1, 2,3, 4 or 5 times from November through April in the Northern Hemisphere.15. The method of claim 1, 2, 3, 4, 5, 6 or 7, wherein the human subjectis a human infant.
 16. The method of claim 1, 2, 3, 4, 5, 6 or 7,wherein the human subject is a human infant born prematurely.
 17. Themethod of claim 1, 2, 3, 4, 5, 6 or 7, wherein the human subject is ahuman subject which has had a bone marrow transplant, a human subject ina nursing home or a human subject which has cystic fibrosis,bronchopulmonary dysplasia, congenital heart disease, congenitalimmunodeficiency or acquired immunodeficiency.
 18. The method of any oneof claims 1, 2, 3, 4, 5, 6 or 7, further comprising administering to thehuman hormonal therapy, immunotherapy or an anti-inflammatory agent. 19.A method of treating or ameliorating a RSV infection or a symptomthereof, said method comprising administering to a human having the RSVinfection an effective amount of a pharmaceutical composition comprisinga carrier or excipient and an antibody, the antibody comprising a VHchain having the amino acid sequence of SEQ ID NO: 254 and a VL chainhaving the amino acid sequence of SEQ ID NO: 255, wherein the antibodyimmunospecifically binds to a RSV F antigen and the effective amount ofthe pharmaceutical composition results in an effective neutralizingtiter of the antibody.
 20. A method of treating or ameliorating a RSVinfection or a symptom thereof, said method comprising administering toa human having the RSV infection an effective amount of a pharmaceuticalcomposition comprising a carrier or excipient and an antibody, theantibody comprising a VH domain having the amino acid sequence of SEQ IDNO: 48 wherein the antibody immunospecifically binds to a RSV F antigenand the effective amount of the pharmaceutical composition results in aneffective neutralizing titer of the antibody.
 21. A method of treatingor ameliorating a RSV infection or a symptom thereof, said methodcomprising administering to a human having the RSV infection aneffective amount of a pharmaceutical composition comprising a carrier orexcipient and an antibody, the antibody comprising a VL domain havingthe amino acid sequence of SEQ ID NO: 11 wherein the antibodyimmunospecifically binds to a RSV F antigen and the effective amount ofthe pharmaceutical composition results in an effective neutralizingtiter of the antibody.
 22. A method of treating or ameliorating a RSVinfection or a symptom thereof, said method comprising administering toa human having the RSV infection an effective amount of a pharmaceuticalcomposition comprising a carrier or excipient and an antibody, theantibody comprising: (a) (1) a VH CDR1 having the amino acid sequence ofSEQ ID NO:10, a VH CDR2 having the amino acid sequence of SEQ ID NO:19,and a VH CDR3 having the amino acid sequence of SEQ ID NO:20, or (2) aVH domain having the amino acid sequence of SEQ ID NO: 48; and (b) (1) aVL CDR1 having the amino acid sequence of SEQ ID NO:39, a VL CDR2 havingthe amino acid sequence of SEQ ID NO:5, and a VL CDR3 having the aminoacid sequence of SEQ ID NO:6, or (2) a VL domain having the amino acidsequence of SEQ ID NO: 11, wherein the antibody immunospecifically bindsto a RSV F antigen and the effective amount of the pharmaceuticalcomposition results in an effective neutralizing titer of the antibody.23. The method of claim 19, 20, 21 or 22, wherein the effective amountis 15 mg/kg or less, 10 mg/kg or less, 5 mg/kg or less or 3 mg/kg orless or 1.5 mg/kg or less.
 24. The method of claim 19, 20, 21 or 22,wherein the effective neutralizing titer is at least 1 μg/ml, at least 2μg/ml, at least 4 μg/ml, at least 6 μg/ml, at least 30 μg/ml, 35 μg/ml,at least 40 μg/ml, at least 50 μg/ml, at least 75 μg/ml, at least 100μg/ml, at least 150 μg/ml or at least 200 μg/ml.
 25. The method of claim19, 20, 21 or 22, wherein the effective neutralizing titer is maintainedfor at least 20 days, at least 25 days or at least 30 days afteradministration of the dose.
 26. The method of claim 19, 20, 21 or 22,wherein the pharmaceutical composition is administered by a nebulizer orinhaler.
 27. The method of claim 19, 20, 21 or 22, wherein thepharmaceutical composition is administered intranasally,intramuscularly, intravenously or subcutaneously.
 28. The method ofclaim 19, 20, 21 or 22, wherein the pharmaceutical composition isadministered 1, 2, 3, 4 or 5 times from November through April in theNorthern Hemisphere.
 29. The method of claim 19, 20, 21 or 22, whereinthe human is a human infant susceptible to an RSV infection.
 30. Themethod of claim 19, 20, 21 or 22, wherein the human is a human infant.31. The method of claim 19, 20, 21 or 22, wherein the human is a humaninfant born prematurely.
 32. The method of claim 19, 20, 21 or 22,wherein the human is a human which has had a bone marrow transplant, ahuman subject in a nursing home, or a human which has cystic fibrosis,bronchopulmonary dysplasia, congenital heart disease, congenitalimmunodeficiency or acquired immunodeficiency.
 33. The method of claim4, wherein the antibody is a monoclonal antibody, chimeric antibody, Fabfragment, F(ab)₂ fragment, single-chain Fv or single chain antibody. 34.A method of preventing a symptom of an RSV infection, said methodcomprising administering to a human an effective amount of an antibodythat immunospecifically binds to a RSV F antigen, wherein the effectiveamount results in an effective neutralizing titer of the antibody, andwherein the antibody comprises a VL chain having the amino acid sequenceof SEQ ID NO:255 and a VH chain having the amino acid sequence of SEQ IDNO:
 254. 35. A method of reducing RSV titers in a human, said methodcomprising administering to a human having a RSV infection an effectiveamount of an antibody that immunospecifically binds to a RSV F antigen,wherein the effective amount of the antibody results in an effectiveneutralizing titer of the antibody, and wherein the antibody comprises aVL chain having the amino acid sequence of SEQ ID NO:255.
 36. A methodof reducing RSV titers in a human, said method comprising administeringto a human having a RSV infection an effective amount of an antibodythat immunospecifically binds to a RSV F antigen, wherein the effectiveamount of the antibody results in an effective neutralizing titer of theantibody, and wherein the antibody comprises a VH chain having the aminoacid sequence of SEQ ID NO:254.
 37. The method of claim 35, wherein theantibody further comprises a VH chain having the amino acid sequence ofSEQ ID NO:254.
 38. A method of reducing RSV titers in a human, saidmethod comprising administering to a human having a RSV infection aneffective amount of an antibody that immunospecifically binds to a RSV Fantigen, wherein the effective amount of the antibody results in aneffective neutralizing titer of the antibody, and wherein the antibodycomprises a VL domain having the amino acid sequence of SEQ ID NO:11.39. A method of reducing RSV titers in a human, said method comprisingadministering to a human having a RSV infection an effective amount ofan antibody that immunospecifically binds to a RSV F antigen, whereinthe effective amount of the antibody results in an effectiveneutralizing titer of the antibody, and wherein the antibody comprises aVH domain having the amino acid sequence of SEQ ID NO:48.
 40. The methodof claim 36, wherein the antibody further comprises a VH domain havingthe amino acid sequence of SEQ ID NO:48.
 41. A method of reducing RSVtiters in a human, said method comprising administering to a humanhaving a RSV infection an effective amount of an antibody thatimmunospecifically binds to a RSV F antigen, wherein the effectiveamount of the antibody results in an effective neutralizing titer of theantibody, and wherein the antibody comprises a VL CDR1 having the aminoacid sequence of SEQ ID NO:39, a VL CDR2 having the amino acid sequenceof SEQ ID NO:5, a VL CDR3 having the amino acid sequence of SEQ ID NO:6,a VH CDR1 having the amino acid sequence of SEQ ID NO: 10, a VH CDR2having the amino acid sequence of SEQ ID NO: 19, and a VH CDR3 havingthe amino acid sequence of SEQ ID NO:20.
 42. A method of inhibiting aRSV infection in a human, said method comprising administering to ahuman an effective amount of an antibody that immunospecifically bindsto a RSV F antigen, wherein the effective amount of the antibody resultsin an effective neutralizing titer of the antibody, and wherein theantibody comprises a VL chain having the amino acid sequence of SEQ IDNO:255.
 43. A method of inhibiting a RSV infection in a human, saidmethod comprising administering to a human an effective amount of anantibody that immunospecifically binds to a RSV F antigen, wherein theeffective amount of the antibody results in an effective neutralizingtiter of the antibody, and wherein the antibody comprises a VH chainhaving the amino acid sequence of SEQ ID NO:254.
 44. The method of claim42, wherein the antibody further comprises a VH chain having the aminoacid sequence of SEQ ID NO:254.
 45. A method of inhibiting a RSVinfection in a human, said method comprising administering to a human aneffective amount of an antibody that immunospecifically binds to a RSV Fantigen, wherein the effective amount of the antibody results in aneffective neutralizing titer of the antibody, and wherein the antibodycomprises a VL domain having the amino acid sequence of SEQ ID NO:11.46. A method of inhibiting a RSV infection in a human, said methodcomprising administering to a human an effective amount of an antibodythat immunospecifically binds to a RSV F antigen, wherein the effectiveamount of the antibody results in an effective neutralizing titer of theantibody, and wherein the antibody comprises a VH domain having theamino acid sequence of SEQ ID NO:48.
 47. The method of claim 45, whereinthe antibody further comprises a VH domain having the amino acidsequence of SEQ ID NO:48.
 48. A method of inhibiting a RSV infection ina human, said method comprising administering to a human an effectiveamount of an antibody that immunospecifically binds to a RSV F antigen,wherein the effective amount of the antibody results in an effectiveneutralizing titer of the antibody, and wherein the antibody comprises aVL CDR1 having the amino acid sequence of SEQ ID NO:39, a VL CDR2 havingthe amino acid sequence of SEQ ID NO:5, a VL CDR3 having the amino acidsequence of SEQ ID NO:6, a VH CDR1 having the amino acid sequence of SEQID NO:10, a VH CDR2 having the amino acid sequence SEQ ID NO:19, and aVH CDR3 having the amino acid sequence of SEQ ID NO:20.
 49. A method ofneutralizing RSV in a human, said method comprising administering to ahuman having a RSV infection an effective amount of an antibody thatimmunospecifically binds to a RSV F antigen, wherein the effectiveamount of the antibody results in an effective neutralizing titer of theantibody, and wherein the antibody comprises a VL chain having the aminoacid sequence of SEQ ID NO:255.
 50. A method of neutralizing RSV in ahuman, said method comprising administering to a human having a RSVinfection an effective amount of an antibody that immunospecificallybinds to a RSV F antigen, wherein the effective amount of the antibodyresults in an effective neutralizing titer of the antibody, and whereinthe antibody comprises a VH chain having the amino acid sequence of SEQID NO:254.
 51. The method of claim 49, wherein the antibody furthercomprises a VH chain having the amino acid sequence of SEQ ID NO:254.52. A method of neutralizing RSV in a human, said method comprisingadministering to a human having a RSV infection an effective amount ofan antibody that immunospecifically binds to a RSV F antigen, whereinthe effective amount of the antibody results in an effectiveneutralizing titer of the antibody, and wherein the antibody comprises aVL domain having the amino acid sequence of SEQ ID NO:11.
 53. A methodof neutralizing RSV in a human, said method comprising administering toa human having a RSV infection an effective amount of an antibody thatimmunospecifically binds to a RSV F antigen, wherein the effectiveamount of the antibody results in an effective neutralizing titer of theantibody, and wherein the antibody comprises a VH domain having theamino acid sequence of SEQ ID NO:48.
 54. The method of claim 52, whereinthe antibody further comprises a VH domain having the amino acidsequence of SEQ ID NO:48.
 55. A method of neutralizing RSV in a human,said method comprising administering to a human having a RSV infectionan effective amount of an antibody that immunospecifically binds to aRSV F antigen, wherein the effective amount of the antibody results inan effective neutralizing titer of the antibody, and wherein theantibody comprises a VL CDR1 having the amino acid sequence of SEQ IDNO:39, a VL CDR2 having the amino acid sequence of SEQ ID NO:5, a VLCDR3 having the amino acid sequence of SEQ ID NO:6, a VH CDR1 having theamino acid sequence of SEQ ID NO: 10, a VH CDR2 having the amino acidsequence of SEQ ID NO: 19, and a VH CDR3 having the amino acid sequenceof SEQ ID NO:20.
 56. The method of claim 38, 39, 40 or 41, wherein theantibody is a monoclonal antibody, chimeric antibody, Fab fragment,(F(ab)₂ fragment, single-chain Fv or single chain antibody.
 57. Themethod of claim 45, 46, 47 or 48, wherein the antibody is a monoclonalantibody, chimeric antibody, Fab fragment, F(ab)₂ fragment, single-chainFv or single chain antibody.
 58. The method of claim 52, 53, 54 or 55wherein the antibody is a monoclonal antibody, chimeric antibody, Fabfragment, F(ab)₂ fragment, single-chain Fv or single chain antibody. 59.The method of claim 34, wherein the antibody is in a pharmaceuticallyacceptable carrier.
 60. The method of claim 37, 40 or 41, wherein theantibody is in a pharmaceutically acceptable carrier.
 61. The method ofclaim 44, 47 or 48, wherein the antibody is in a pharmaceuticallyacceptable carrier.
 62. The method of claim 51, 54 or 55, wherein theantibody is in a pharmaceutically acceptable carrier.
 63. The method ofclaim 34, wherein the effective amount is approximately 15 mg/kg orless.
 64. The method of claim 37, 40 or 41, wherein the effective amountis approximately 15 mg/kg or less.
 65. The method of claim 44, 47 or 48,wherein the effective amount is approximately 15 mg/kg or less.
 66. Themethod of claim 51, 54 or 55, wherein the effective amount isapproximately 15 mg/kg or less.
 67. The method of claim 34, wherein theantibody is administered intramuscularly.
 68. The method of claim 37, 40or 41, wherein the antibody is administered intramuscularly.
 69. Themethod of claim 44, 47 or 48, wherein the antibody is administeredintramuscularly.
 70. The method of claim 51, 54 or 55, wherein theantibody is administered intramuscularly.
 71. The method of claim 34,wherein the antibody is administered 5 times from November through Aprilin the Northern Hemisphere.
 72. The method of claim 37, 40 or 41,wherein the antibody is administered 5 times from November through Aprilin the Northern Hemisphere.
 73. The method of claim 44, 47 or 48,wherein the antibody is administered 5 times from November through Aprilin the Northern Hemisphere.
 74. The method of claim 51, 54 or 55,wherein the antibody is administered 5 times from November through Aprilin the Northern Hemisphere.
 75. The method of claim 34, wherein thehuman is a human infant.
 76. The method of claim 37, 40 or 41, whereinthe human is a human infant.
 77. The method of claim 44, 47 or 48,wherein the human is a human infant.
 78. The method of claim 51, 54 or55, wherein the human is a human infant.
 79. The method of claim 44, 47or 50, wherein the human is a human infant susceptible to an RSVinfection.
 80. The method of claim 51, 54 or 55, wherein the human is ahuman infant susceptible to an RSV infection.
 81. The method of claim34, wherein the human is a human infant born prematurely.
 82. The methodof claim 37, 40 or 41, wherein the human is a human infant bornprematurely.
 83. The method of claim 44, 47 or 48, wherein the human isa human infant born prematurely.
 84. The method of claim 51, 54 or 55,wherein the human is a human infant born prematurely.
 85. The method ofclaim 34, wherein the human is a human which has had a bone marrowtransplant, or a human which has cystic fibrosis, bronchopulmonarydysplasia, congenital heart disease, congenital immunodeficiency oracquired immunodeficiency.
 86. The method of claim 37, 40 or 41, whereinthe human is a human which has had a bone marrow transplant, or a humanwhich has cystic fibrosis, bronchopulmonary dysplasia, congenital heartdisease, congenital immunodeficiency or acquired immunodeficiency. 87.The method of claim 44, 47 or 48, wherein the human is a human which hashad a bone marrow transplant, or a human which has cystic fibrosis,bronchopulmonary dysplasia, congenital heart disease, congenitalimmunodeficiency or acquired immunodeficiency.
 88. The method of claim51, 54 or 55, wherein the human is a human which has had a bone marrowtransplant, or a human which has cystic fibrosis, bronchopulmonarydysplasia, congenital heart disease, congenital immunodeficiency oracquired immunodeficiency.
 89. The method of claim 34, wherein the humanis in a nursing home.
 90. The method of claim 37, 40 or 41, wherein thehuman is in a nursing home.
 91. The method of claim 44, 47 or 48,wherein the human is in a nursing home.
 92. The method of claim 51, 54or 55, wherein the human is in a nursing home.
 93. The method of claim37, 40 or 41, further comprising administering to the human hormonaltherapy, immunotherapy or an anti-inflammatory agent.
 94. The method ofclaim 44, 47 or 48, further comprising administering to the humanhormonal therapy, immunotherapy or an anti-inflammatory agent
 95. Themethod of claim 51, 54 or 55, further comprising administering to thehuman hormonal therapy, immunotherapy or an anti-inflammatory agent.